Whether it is the growth in co-working spaces around the world full of 20 and 30-somethings starting their own thing, to TV shows on entrepreneurship, all the way to the big successes out of California’s Silicon Valley, the millennial generation are attracted to starting their own businesses. However, it is not just about making money but also about passion and doing good. Christine Selph from Deloitte and professor Ethan Mollick from the Wharton School of Business give us an overview of this generation and of entrepreneurship. We go to a session run by Pop Up Business School to speak to some millennials about their motivations. Ayzh founder Zubaida Bai and Upstart founder Richard Dacalos tell us about the power of social entrepreneurship to solve problems which can be neglected by governments, while former World Bank economist Charles Kenny cautions us about focusing too much on the individual at the expense of government. Presenter and producer: Nastaran Tavakoli-Far Editor: Andrew Smith

We can now curate who we talk to in a way that wasn’t thinkable when a bulky landline phone sat in a corner of a house and rang with anonymous urgency. The screens on our devices allow us to communicate in any number of quick, cheap but silent ways.These modern technologies are very useful, which is why they are so ubiquitous, but are they taking something from us that is deeply human? Sandra Kanthal asks why we choose to text instead of talk, and if this incredibly popular form of communication is changing the way we interact and relate with each other. Contributors: Gary Turk - Spoken Word Artist/Poet Sherry Turkle - Professor of the Social Studies of Technology, MIT and Author, Reclaiming Conversation: How To Talk In The Digital Age Sophie Scott - Director of the Institute of Cognitive Neuroscience, University College London Mary Jane Copps - Owner, The Phone Lady Chetan Deshpande - Digital Sales and Profit Consultant

Physical scars can be sources of shame or badges of honour: acquired accidentally or a cry for help. How should we read them, and what do they tell us about ourselves and our place in the world? We explore the practice of scarification, intentional body modification which has been practised for millennia, where scars denote status within tribal communities and are worn with pride. Brent Kerehona tells us about the type of scarification he has: Ta Moko. We meet stuntman Andreas Petrides, who has been Obi-Wan Kenobi’s stunt double. He also wears his scars with pride, but for different reasons: they are trophies of his profession. For millions, scars can be sources of embarrassment. We examine the constructs of beauty that might underpin those feelings. We speak to Hemani Modasia, who suffered scarring from burns to 35% of her body when she was a child, and who wishes, ultimately, she never had them. Scars can also be interpreted as a cry for help, transversing the space between the physical and the deeply emotional. Japanese photographer Kosuke Okahara tells us about his project which captured the scars of Japanese women who suffered from self-harm across a period of 6 years. Former Vogue editor Jackie Dixon, tells us the fashion industry is now embracing scars - they are part of the zeitgeist. We spoke to Jackie at a photoshoot in central London, where she was photographing a model for a book she is producing that celebrates scars. The programme also hears from Professor Parashkev Nachev, a neurologist at University College London, and Nichola Rumsey, founder of the Centre for Appearance Research at the University of the West of England. Parashkev tells us the creation of scars is not fully captured by science, suggesting they are both deeply mysterious and profoundly human. Nichola places scars in a social context, and points out they often render us outliers which, for many people, is challenging and uncomfortable. Presenter: Christopher Gunness Producer: Oliver Newlan Editor: Carl Johnston (Image: Hemani Modasia. Credit: Spencer Murphy for the Scar Free Foundation)

Dystopic fiction is going through a bit of a boom at the moment, but why is it that we can’t seem to get enough of stories where ordinary people struggle to survive against an all-powerful state, or in a post-apocalyptic world? Is it because they reflect the anxieties we already feel about the world we live in, or because they allow us to escape it? Shabnam Grewal asks: Why is dystopic fiction so appealing? Produced and presented by Shabnam Grewal Editor: Andrew Smith (Photo: Destroyed cityscape. Credit: Stock Photo/Getty Images)

The trauma of sexual assault is both personal and brutal. But what may be an indisputably traumatic event for one person is often challenged by another, and the responsibility for events gets scattered in the process. Why is it so common for people to look for reasons to blame the victims of sexual assault for what has happened to them? Nastaran Tavakoli-Far finds multiple reasons from this, speaking to experts and to victims. We hear from Dr Mithu Sanyal about the role of long-standing attitudes towards gender and sexuality. New York Times journalists Jodi Kantor and Megan Twohey tell us about power and the workplace and who is more likely to be believed. Dr Jackson Katz and Dr Laura Niemi explain the roles of both group dynamics and the language we use and how these often work to protect perpetrators rather than to support victims Presenter and producer: Nastaran Tavakoli-Far Editor: Andrew Smith (Photo: Protest sign held up during 'Slut Walk' protests against victim blaming in Munich, Germany / Credit: Alexander Pohl / Nur Photo / Getty Images)

It’s the festive season, which means there are lots of parties going on. If you’re planning a party, what kind of celebration will it be? Organising the right food, drink and, crucially, guest list requires time and effort. Party planning has been listed as one of the most stressful professions you can have so, in the spirit of the season, in this edition of the Why Factor, Sandra Kanthal is asking: why is it so hard to plan the perfect party? Contributors: Claire Derrick: Co-founder, The Event Academy Rosie Hart: Course Director, The Event Academy Kim Glasgow and Henry Khan: Students, The Event Academy Liz Taylor: Managing Director, Taylor Lynn Corporation Robin Dunbar: Professor of Evolutionary Psychology – Oxford University Priya Parker: Author, The Art of Gathering – How We Meet and Why It Matters

Resilience is one of the buzzwords of the moment with multiple self-helps books and motivational speakers all promising us we can learn to be resilient, and use this skill to manage our pain. But what exactly is resilience and why does it help some people to cope better in times of stress than others? In this Why Factor, Abby Hollick examines why some people, in the face of trauma, seem to be extraordinarily resilient and tests her own inner reserves to discover if she is naturally resilient or not. Dr David Westley, head of psychology at Middlesex University Ann Masten, professor at the University of Minnesota Lucy Wairimu Mkuria, psychologist Dr Nimmi Hutnik, author of Becoming Resilient: Cognitive Behaviour Therapy to Transform Your Life Melanie Reid, journalist for The Times Dr Atle Dyregrov, clinical psychologist and Director of the Centre for Crisis Psychology in Bergen. Presenter and Producer: Abby Hollick Editor: Andrew Smith (Photo: Man being rescued by two firefighters. Credit: Getty Images / Stock Photo)

An exploration of why and how music can exert a powerful effect on our emotions. Why does one particular collection of notes make us want to get up and dance, and another calm us down? Edwina Pitman hears from record producer turned neuroscientist Daniel Levitin about how our brains process music and from psychologist Victoria Williamson about how we react to the memories that sounds trigger. Renowned Hollywood film composer Brian Tyler demonstrates how he creates music that reflects the many shades of emotional grey between happy and sad, and Emmanuel Jal, the South Sudanese-Canadian musician and former child soldier, reveals how music helped him come to terms with the trauma of his childhood. Guests: Bryan Tyler - film composer and conductor Dr Daniel Levitin - neuroscientist, and Founding Dean of Arts & Humanities at The Minerva Schools at KGI and author of This Is Your Brain On Music Dr Victoria Williamson - Lecturer in Music Psychology at the University of Sheffield and author of You Are The Music Rob Wood - founder of Music Concierge Bibi Heal - opera singer Emmanuel Jal - singer and musician Presented and produced by Edwina Pitman Editor: Andy Smith

Many men believe their gender is under siege from a welter of criticism about male attitudes and behaviours. Not everyone accepts the idea of a masculinity crisis, but this programme looks at the concept of the “man box” – a set of attitudes and assumptions which many males struggle to deal with. Artist Grayson Perry joins the discussion. Presenter: Michael Blastland Producer: Anna Meisel Editor: Andy Smith (Photo: James Mace, Barber. Credit: Ian Burt)

Asked to describe your grandparents, you may conjure fond childhood memories of trips to the park or going round for your favourite dinner after school. You may live just around the corner and see your grandparents daily or they might be a welcome voice on the phone, brightening your day from afar. Elaine Chong discovers just why it is that grandparents matter so much to us and she finds out what happens when grandparents step in to raise their grandchildren. In the township of Umlazi, near Durban in South Africa, she meets a group of grandmothers who are raising their grandchildren singlehandedly, after the children lost their parents in the Aids pandemic. She uncovers research showing grandmothers have played a vital role in the survival of their grandchildren for centuries, especially before modern medicine and support services existed. She hears the incredible story of an 11-year-old boy who is being raised by his grandparents and repays their devotion, by saving his grandad’s life. Have you ever stopped to consider why your grandparents hold such a dear place in your heart? Elaine hears evidence all those childhood visits, trips and gatherings play an important and lasting role in shaping our personalities. Presenter: Elaine Chong Producers: Ben Robinson, Nicola Dowling and Carl Johnston Editor: Andy Smith (Photo:Grandmother’s at the Community Centre, Umlazi, South Africa. Credit Nkosinathi Shange)

Infidelity is seen as the ultimate betrayal, and many relationships are brought down by it. Around the world most of us agree that it’s wrong for a married person to have an affair, but that doesn’t seem to stop us: why? The answer could lie in our DNA. In this week’s Why Factor, Phoebe Keane hears how research into the mating habits of prairie voles could shed light on the extra marital affairs of humans and explores how we make decisions in the heat of the moment. Guests: Professor Steven Phelps, University of Texas at Austin Assistant Professor Andrea Meltzer, Florida State University Professor Lucia O’Sullivan, University of New Brunswick Nicolle Zapien, Professor California Institute of Integral Studies, Psychotherapist, and Sex Therapist Presented and Produced by Phoebe Keane Editor: Richard Knight

It turns out that much of what we do – much of our behaviour – can be conducted at an unconscious level. That raises a profound question. What is the point of consciousness? What evolutionary advantage does consciousness bestow? We speak to psychologists and neuroscientists for the answer. And we ask a philosopher whether science can ever unravel the deep mysteries of consciousness. The programme is guaranteed to hurt your brain. Presenter and producer: David Edmonds Editor: Richard Knight (Photo: / Credit: Doorway to another world - stock photo. Getty Images)

Sleep, day-dreaming, meditation – these are all different states of awareness. In these states we are not really aware of what is going on around us. But even when humans are awake, we take in very little about our surroundings. So this week we speak to psychologists and neuroscientists to ask, why are we conscious of so little? Presenter and producer: David Edmonds Editor: Richard Knight (Photo: X-ray image of human head with lightning / Credit: Getty Images)

About half the population consider themselves to have a shy personality, but most of us feel shyness in certain situations. Although some people may display outward signs of shyness such as blushing and being tongue-tied, shyness isn’t always visible to others; a surprising number of extroverts and performers are shy. Edwina Pitman examines what it means to be shy and attitudes towards shyness. Professor Susie Scott, Professor of Sociology, University of Sussex Kristie Poole, Department of Psychology, Neuroscience & Behaviour, McMaster University Professor Joe Moran, Professor of English and cultural history at Liverpool John Moores University and author of Shrinking Violets, A Field Guide to Shyness Sylvie Guillem, Ballet Dancer Susan Cain, Author of Quiet: The Power of Introverts in a World That Can't Stop Talking Members of The London Shyness Social Group Professor Yiyuan Xu, Professor of Psychology, University of Hawaii at Manoa Presented and produced by Edwina Pitman Editor: Richard Knight (Photo: Woman wearing paper bag. Credit: Stock Photo / Getty Images)

In the second and final part exploring intuition Nastaran Tavakoli-Far speaks to cricket players who used data to win championships and hears about business leaders who trumpet their successes and forget the times their intuition led to failure. She talks to psychologists and Nobel Prize winners about why we get so attached to our intuitions and forget the times it was wrong, and why we should probably use a mix of both intuition and rational analysis when making decisions. Alex Wakely – former Northamptonshire County Cricket Captain David Ripley – Northamptonshire County Cricket Coach Thomas Gilovich – Professor of Psychology, Cornell University Daniel Kahneman – Winner of the 2002 Nobel Prize in Economic Sciences, Psychology Professor at Princeton University, author of ‘Thinking Fast and Slow’ Eric Bonabeau – Chief Scientific Officer, Telepathy Labs Prof Gary Klein – Cognitive Psychologist and President of Shadowbox LLC Right Honourable Lord David Willetts – Resolution Foundation and former UK Minster for Universities and Science Presenter and producer: Nastaran Tavakoli-Far Editor: Richard Knight (Photo: Toddler looking at a birthday cake on a table. Credit: Stock Photo. Getty Images)

In part one of two episodes exploring intuition, Nastaran Tavakoli-Far speaks to a detective who had an intuition that someone was a serial killer, as well as hearing stories about firefighters who saved themselves from death after listening to their intuition. She also speaks to psychologists, neuroscientists and a Nobel Prize winning economist to find out more about how intuition is formed and how it works, and also hears about intuition’s role in the world of politics. Detective David Swindle – Head of Crime Solutions Prof Gary Klein – Cognitive Psychologist and President of Shadowbox LLC Prof Daniel Kahneman – winner of the 2002 Nobel Prize in in Economic Sciences, Psychology Professor at Princeton University, author of ‘Thinking fast and slow’ Prof Antonio Damasio – professor of neuroscience and psychology at the University of Southern California and director of the Brain and Creativity Institute Dr Michelle Wright – Investigative Psychology Researcher and Chartered Psychologist Right Honourable Lord David Willetts – Resolution Foundation and former UK Minster for Universities and Science Presenter and Producer: Nastaran Tavakoli-Far Editor: Richard Knight (Image: Firefighter and Fire. Credit: Stock Photo. Getty Images )

From instant messaging, to online shopping and even smart fridges, we live in a connected age where all of life’s essentials can be obtained at the click of a button. So why do so many people ditch the trappings of modern life and head off into the countryside with a tent? In this week’s episode of the Why Factor adventure journalist Phoebe Smith sets out on a journey to discover what makes camping so special. Along the way she discovers a camper in Kenya who spends his weekends alone immersed in nature, a family in Greenland who turned their backs on the rat race to live in a tepee and she even convinces her dad to join her for a night’s wild camping on an island in the River Thames in England. She discovers that leaving our phones and tablets behind to spend a few peaceful nights under the stars might not just be a good way to unwind but research shows it can improve our sleep patterns and well-being. So the question is why aren’t we all doing it? Reporter: Phoebe Smith Producers: Nicola Dowling, Oliver Newlan and Ben Robinson Editor: Carl Johnston (Photo: Camping at Mount Kenya. Credit: Martin Ngugi / Getty Images)

All over the world there are people rejecting the society they live in and choosing radically different pathways. Some are abandoning the idea of a ‘family house’ in favour of a nomadic, solitary life in a camper van. They live frugally as they travel around the country, or even the world, in their tiny homes. Others go in a different direction, seeking a life which fulfils them and aligns with their values. They may end up in an ‘intentional community’, where both income and property are shared. Some choose to withdraw their children from formal education and instead allow them to follow their own interests, learning what they think they need to, when they need to. Others go even further. They want to run their own country, or micro-nation, so they can live under laws and legislation they believe in. On the Why Factor this week, Shabnam Grewal meets people who reject the society they live in, and choose instead to carve out their own way. Presented and produced by Shabnam Grewal Editor: Richard Knight (Image: Woman looks out the back of her camping van. Credit: Stock Photo/Getty Images)

Statistics from around the world show huge improvements to our way of life, but many of us think the world is in decline. There are good reasons for this; climate change is often cited as the big one. But many of us aren’t aware of the huge strides we’ve made over the decades in reducing poverty, improving healthcare and tackling hunger. In fact, according to surveys of people in richer countries at least, the majority of people think the world is getting worse; but why? In this edition of the Why Factor, Sandra Kanthal asks if human nature is wired to fixate on the downsides of life. Professor Martin Seligman, Director of the Positive Psychology centre at the University of Pennsylvania Dr Hannah Ritchie, Head of Research at Our World in Data Ola Rosling , Director and Co-founder of the Gapminder Foundation Chris Martenson, Co-founder and CEO of Peak Prosperity Professor Jeremy Adleman, Director of The Global History Lab at Princeton University Steven Pinker, Professor of Psychology at Harvard University Presenter: Sandra Kanthal Producer: Xavier Zapata (Image: Woman on a train looking out of the window. Credit: Marjan Apostolovic/Getty Images)

In the 1970s, second wave feminists declared war on make-up - arguing it oppressed women, distracted them from gaining equality, and forced them to attain a beauty ideal not expected of men. And yet young women today wear more make-up than ever. Women have made gains in employment, education, sexual liberation, so why is it so many of us can’t leave the house without make-up? We explore the power and allure of mak-eup and why it works. Presented and Produced by Gemma Newby Editor: Richard Knight (Photo: Young woman vlogging about beauty products. Credit: Getty Images)

What does happiness mean to you? Friends, family, the rush of a crowd or the joy of solitude? Happiness is a fundamental human desire, yet we often struggle to achieve it. Understanding what does and does not make us happy is a growing field of scientific study. In this edition of The Why Factor, Sandra Kanthal asks if we can really teach people how to be happy. Laurie Santos – Professor of Psychology, Yale University Bruce Hood – Professor of Developmental Psychology, University of Bristol Ellie Wright – Student, University of Bristol Meike Wiking – CEO, Happiness Research Institute Jan-Emmanuel de Neve – Associate Editor, World Happiness Report Professor Dixon Chibanda – Psychiatrist and Founder of The Friendship Bench Project (Photo: Notepad and smile emoticon on books. Credit: Getty Images)

Christopher Gunness explores why funerals matter so profoundly to us, as individuals and societies. He talks to people who have lost loved ones in Ghana, Pakistan and the UK about the challenges they have faced. He discovers how burial and cremation have become popular in different countries at different times, visits a green burial place and looks at the growing world of online memorials. Presenter: Christopher Gunness Producer: Bob Howard (Photo: Ghana, Accra Funeral Service. Credit: Getty Images)

Blending ingredients to produce something new is a distinctively human urge, and one of our most creative acts. We blend all sorts of products, such as tea, champagne and perfume. Did you know that blended whiskies combine over 30 single malts? In this week’s Why Factor, Barry Smith asks - why we blend. And why some blends work whilst others don’t. Presenter: Barry Smith Producer: David Edmonds Editor: Richard Knight

As the world grows more urban, humanity moves further away from nature. Could this be the reason anxiety has become the most diagnosed mental illness in the west? The idea of mindfulness is becoming more popular as the mainstream grows more aware of how panicked we all are. How are we tackling this issue? Jordan Dunbar dives into a niche of researchers and therapists who are learning about and treating the negative symptoms of urban life with a dose of nature. Lea Kendall, Therapist and James Kendall, Wilderness Instructor Birgitta Gatersleben, Environmental Psychologist Patricia Hasbach, Clinical Psychotherapist Harini Negrenda, Professor of Sustainability at Azim Premji University, Bangalore, India Layla McCay, Centre for Urban Design and Mental Health Presented and Produced by Jordan Dunbar Researcher Julia Webster Editor Richard Knight

The sports teams we support say something about who we are. Our identities are bound up with the men and women who play for our side – and we experience their success and failure as if they were our own. But, if supporting your team is so important, how can there be so many people who think these contests are of little consequence? Sandra Kanthal explores why we care so deeply about the outcome of a game. Michael Sandel, professor of Government Theory - Harvard University Dr Martha Newson, cognitive anthropologist - Oxford University Dr Alan Pringle, faculty of Medicine and Health Sciences - University of Nottingham Stephen Reicher, professor of Social Psychology -University of St Andrews Matthew Engel, sportswriter and author of That’s the Way It Crumbles Nisha Nair, assistant professor of Business Administration – University of Pittsburgh (Photo: Pakistan cricket superfans. Credit: Mohammed Arif, ECB National Growth Manager, Diverse Communities)

If the idea of being all alone, in silence, for long periods of time fills you with dread, it might be hard to understand why anyone would choose to be a hermit. But throughout history and across all cultures, there have been people who choose to leave behind the life and people they know to live in isolation and silence. This week, Shabnam Grewal asks: why do people become hermits? Guests: Sara Maitland - writer, feminist and Catholic hermit. Ansuman Biswas - artist and part-time hermit Michael Finkel - writer of The Stranger in the Woods, about American hermit Christopher Knight Meng Hu - former librarian who runs a website called Hermitary Prof Takahiro Kato - psychiatrist who specialises in hikikomori Music by Ansuman Biswas and Stanley Keach. Image: An isolated log cabin (Credit: Getty Images)

Open plan offices, hot-desking, group brainstorming sessions: collaboration seems to be king in the modern workplace. Recent studies have found that we are spending up to 80% of our working days either in meetings or dealing with requests from our colleagues. But is working together really the best way? Is the idea of collaboration something we’re fetishising at the cost of productivity and creativity, and have we lost sight of the benefits of working alone? Nastaran Tavakoli-Far shares her own dislike of the BBC’s open-plan office and asks, in some desperation: why should we work together? Guests: Art Markman, professor of psychology and marketing at the University of Texas at Austin, and author of Bring Your Brain to Work Kerstin Sailer, reader in social and spatial networks, The Bartlett School of Architecture, University College London Susan Cain, author of Quiet: The Power of Introverts in a World That Can't Stop Talking John Maeda, global head of design at Automattic Image: Workers in an open-plan office (Credit: Getty Images)

Schadenfreude is a German word that means “harm-joy”. It is the pleasure we feel from someone else’s misfortune, and it can come in many shades. It is the laughter we can’t stifle when someone unexpectedly falls over, or the triumphant pleasure we feel when a rival is defeated. We can also feel it when something bad happens to someone we genuinely like. Edwina Pitman examines why, even when we’re happy and successful, we can’t help but enjoy others’ bad luck. Contributors: Esther Walker - journalist Dr Tiffany Watt Smith - cultural historian and author of Schadenfreude: The Joy of Another’s Misfortune Professor Richard Smith - professor of psychology, University of Kentucky Dr Andre Szameitat - reader in psychology, Brunel University Anuvab Pal - Comedian Mike Wendling - Editor, BBC Trending Presented and produced by Edwina Pitman Editor: Richard Knight (Photo: Cheerful young woman lying on sofa with laptop in modern office lounge. Credit: Getty Images)

The history of computing is filled with the accomplishments of women. But in the West, the number of women taking computer science degrees has fallen sharply from its peak in the 1980s. In the developing world, however, the trend is going in the other direction, because learning to code offers economic opportunities not available to women before. Women are still outnumbered in computer science classrooms, but there are more of them. In this edition of The Why Factor on the BBC World Service, Sandra Kanthal asks why there areso few women in computer science, and what is driving them from a field they helped to create? Guests: Dame Wendy Hall, Regius Professor of Computer Science, University of Southampton Dr Barbara Ericson, Assistant Professor of Information, University of Michigan Dr Anjali Das, Head of Learning, Centre for Computing History Miriam Posner, Assistant Professor of Information Studies and Digital Humanities, UCLA Noemi Titarenco, Software leader and product manager, Los Angeles Fereshteh Forough, Founder: Code To Inspire Apple Macintosh Commercial – 1984 produced by Fairbanks Films Image: A woman studies a computer screen (Credit: Getty Images)

Most of us feel some need to know a roadmap of our past, our connections with a family tree which took root before we were born. We look for stories to tell about where we come from and seek answers in the lives of our ancestors, even in the DNA they pass on to us. In this edition of the Why Factor, Viv Jones asks why we have such a fundamental need to discover the stories of our heritage, and what they tell us about ourselves. Contributors: Sandy Banks, journalist Caitriona Palmer, author of ‘An Affair With My Mother’ Fenella Cannell, Associate Professor Of Anthropology, London School of Economics Tim Caulfield, Canada Research Chair in Health Law and Policy, University of Alberta Catherine St Clair, founder of NPE Friends Fellowship Image: Woman admiring the sunset Credit: Getty Images

What makes some people want to base jump off a building, or climb a cliff with no ropes? A thrill-seeking personality may be necessary, but is it enough to court the sort of danger that could kill? In this week's Why Factor, we explore why some people risk death in pursuit of adventure. CONTRIBUTORS Hazel Findlay, Professional climber. Erik Monasterio, consultant in Forensic Psychiatry, clinical director of the regional forensic service in Canterbury New Zealand and senior clinical lecturer with the University of Otago. Mary Philips, Professor in Psychiatry in chemical and translational science, University of Pittsburgh Medical Center. Tim Woodman, Professor of Psychology, School of Sport Health and Life Sciences at Bangor University. Roberta Mancino, BASE jumper and stunt woman. Rob Fletcher, associate professor of sociology of development and change at Hanagen University in the Netherlands. Steven Lyng, Professor emeritus at Carthage College and Kenosha Wisconsin. Photo: Male climber gripping on handhold while climbing in cave Credit: Getty Images

Our attitude to taxation is determined by a wide range of factors: whether we think our neighbours are tax dodgers, how much control we have over how funds are spent and even our gender, age and religious beliefs. Nastaran Tavakoli-Far hears tales of tax avoidance by the world’s super-rich and finds out how governments around the world are using simple ‘nudge’ techniques to get people to feel positive about paying up. Guests: Carla Gericke, President Emeritus of the Free State Project Brooke Harrington, Professor of Sociology, Dartmouth College Stewart Kettle, Senior Advisor at the Behavioural Insights Team Jan-Emmanuel De Neve, Associate Professor of Economics and Strategy at Saïd Business School Benno Torgler, Professor of Economics in the School of Economics and Finance, QUT Kelly Sarri, filmmaker Photo: Calculating Tax Credit: Getty Images

How confidence can motivate, get us off the couch, make us healthier, enterprising, decisive and help us live up to our potential We also learn how doctors, entrepreneurs and whole economies can benefit from the right kind of confidence and the ways in which we can tell the good from the bad. In this edition of the Why Factor, Michael Blastland asks: why do we admire confidence? Contributors: Ed O’Brien - Associate Professor of Behaviour Science, University of Chicago Booth School of Business Maria Konnikova - Psychologist and Author: The Confidence Game Dr. Tomas Chamorro-Premuzic - Psychologist and Author: Confidence, The Surprising Truth About How Much You Need and How To Get It. Dr Anne McGuinness – University College London Hospitals NHS Foundation Trust Dr Josephine Perry – Sports Psychologist Don Moore – Professor of Management of Organizations, Haas School of Business at the University of California, Berkeley

From doctors to politicians to your boss, people often ask us to put our confidence in them. We’re often urged to build more confidence in ourselves. But one of the most consistent findings in psychology is that there is very little overlap between confidence and competence; how good people think they are, and how good they really are. In this edition of the Why Factor, Michael Blastland asks: why do admire confidence? Contributors Ed O’Brien - Associate Professor of Behaviour Science, University of Chicago Booth School of Business Maria Konnikova, Psychologist and Author: The Confidence Game Dr. Tomas Chamorro-Premuzic, Psychologist and Author: Confidence, The Surprising Truth About How Much You Need and How To Get It. Glen Fukushima -Senior Fellow, Center For American Progress Dr Anne McGuinness – University College London Hospitals NHS Foundation Trust Photo Credit: Multiple exposure of businesswoman arms crossed / Getty Images Film Credit: The Great Imposter Trailer 1960 / Universal Studios Home Entertainment / Director Robert Mulligan

At some point in our lives, we’re all likely to make an investment, in time or money or effort, which goes wrong. But, when we know we’re in a hole, why do we find it so hard to stop digging? Realising when we should cut our losses is a decision making skill that’s important in all areas of our lives. In this Why Factor Sandra Kanthal examines why we should all learn how to avoid the 'sunk cost' fallacy. Guests: Spencer Christian - author, You Bet Your Life Wandi Bruine de Bruin - professor of behavioural decision making, Leeds University Business School Dean Yeong - Malaysian writer and entrepreneur Lior Sheffer – post-doctoral fellow, Department of Political Science, University of Toronto Christopher Olivola - assistant professor of marketing, Tepper School of Business, Carnegie Mellon University Claire Gregory – co-founder, The Female Fitness Academy Presented and produced by Sandra Kanthal Editor: Richard Knight

Many jobs require workers to manage their emotional expressions with others. Flight attendants are expected to smile and be friendly even in stressful situations, carers are expected to show empathy and warmth, whereas bouncers and prison guards might need to be stern or aggressive. This management of emotions as part of a job is called ‘emotional labour’. It is something many people perform on top of the physical and mental labour involved in their work. Psychologists have shown that faking emotions at work, and suppressing real feelings, can cause stress, exhaustion and burnout. These efforts can be invisible, and that sometimes allows employers to exploit them. Nastaran Tavakoli-Far speaks to sociologists, psychologist, economists and bartenders and asks why we should value emotional labour.

People on the left are more likely to accept climate change than those on the right in the USA, Australia and much of Western Europe. But it’s a question that starts with little more than a thermometer, a measurement of the temperature at the earth’s surface. Why does a science question divide people along party lines? Was it the oil industry, fuelling doubt about the science? Or something deep in our psychology, that causes us to push the science aside in favour of belonging to a tribe, a feeling that who our friends are and what they believe, matters more? Presenter: Michael Blastland Producer: Phoebe Keane Editor: Richard Vadon

Why can’t we judge art at face value? How does the identity, behaviour and cultural context of the artist play a part in how we approach their artwork? Edwina Pitman explores why we can’t seem to separate the art from the artist. Guests: John Myatt, artist Paul Bloom, Professor of psychology and cognitive science at Yale University Michelle Hartney, artist Lionel Shriver, novelist Ananya Mishra, PhD researcher in English, University of Cambridge Svetlana Mintcheva, Director of Programs, National Coalition Against Censorship, New York Bob Sturm, Associate Professor in Speech, Music and Hearing at Royal Institute of Technology, Stockholm Presented and Produced by Edwina Pitman Editor: Richard Knight (Photo: Woman looking at the Pablo Picasso painting The Dream. Credit: Leon Neal/Getty Images)

Popularly known through the1950 Disney film of the same name, Cinderella has become a childhood classic all over the world. But different versions of her story can be traced all the way from Asia to Africa and beyond. These variants provide a snapshot of the history and cultures from which they emerge, providing clues to the tale’s longevity. In this episode Sandra Kanthal asks: Why is Cinderella such a popular story to tell. Guests: Gessica Martini – PhD Student, Durham University Juwen Zhang – Professor of Chinese, Willamette University Rym Tina Ghazal – Author and Journalist Ousseina Alidou – Professor of African Languages and Literatures, Rutgers University Dee Dee Chainey – Author and Co-founder of Folklore Thursday Editor: Richard Knight Producer: Tural Ahmedzade Photo: Cinderella About to Try on the Glass Slipper by Richard Redgrave Credit: Historical Picture Archive/Corbis via Getty Images

Telling stories is one of the ways we connect to one and other. Stories teach us empathy and allow us to feel what it’s like to walk in someone else’s shoes. They evolve to show us what our society considers acceptable - and what will not be forgiven. Sandra Kanthal explores why stories matter. Guests: David JP Philips – Communications Expert John Yorke - Author: Into The Woods Mirta Galesic - Professor in Human Social Dynamics, Santa Fe Institute Jamie Tehrani, Associate Professor of Anthropology, Durham University Elizabeth Kperrun - Founder; Zenafri Limited Samantha Armstrong - Senior Publisher, Oxford University Press Sandra Newman – Author: The Heavens and How Not To Write a Novel Music Track: Make America Great Again – performed by Dave Fenley (Photo: Woman holding an open book bursting with light. Credit: Getty Images)

Is there any truth to claim that the mother daughter relationship is more fraught than any other dynamic? Psychologist Professor Terri Apter explains how conflict can help mothers and daughters renew their bond. Mother and daughter team Sally and Sarah Kettle advocate shared experience as a way to strengthen family ties, something they found while rowing across the Atlantic together for four months, and comedian Sindhu Vee talks about the unique features of a mother’s expectations. We also hear how, despite the best of intentions, many mothers can disempower their daughters in order to thrive in a patriarchy. Author and women’s rights activist Elif Shafak warns about the ways daughters are taught to blend in, especially in cultures which are more gendered. Dr Leyla Hussein has had first-hand experience of female genital mutilation, and explains how women have become the foot soldiers of a patriarchal system that promotes such practises. Writer and matriarchy scholar Vicki Noble describes how the mother daughter dynamic is different in societies where women wield power, and life coach Kasia Urbaniak, who teaches women the foundations of power and influence, explains what a mother can do to empower her daughter. Presenter: Nastaran Tavakoli-Far Producer: Edwina Pitman Editor: Richard Knight Photo: Mother and daughter together. Credit: Getty Images

Fathers are often regarded as secondary parents in many cultures, perhaps even more so when they have girls. We examine why this can be damaging, and the ways in which fathers can have a profound influence on how their daughters navigate the world. Evolutionary anthropologist Dr Anna Machin explains why human fathers are in the only five per cent of mammals that stick around after the birth of their offspring, and why that’s important, particularly for girls. Father and daughter team Jerry and Chloe Hughes, who run a fine art foundry, talk about how working together has changed their family dynamic for the better. We also look at the consequences of a dysfunctional father-daughter relationship. Professor of Adolescent and Educational Psychology Dr Linda Nielsen describes how a poor relationship with a father affects a daughter’s life choices well into adulthood. Writer and podcaster Carvell Wallace gives some sage parenting advice to fathers of teenage girls, and we hear from Australian dad Jonathan Poyter, who took part in a 13-week programme called DADEE at Newcastle University in Australia, where dads and daughters learn to bond through sports. And it’s not just a one way street. Dr Joan Costa-Font, professor in the Department of Health Policy at the London School of Economics, tells us about his latest research, which shows that daughters also have a big impact on the behaviour of their fathers. Presenter: Nastaran Tavakoli-Far Producer: Edwina Pitman Editor: Richard Knight Photo: A father and daughter playing (Credit: Getty Images)

We are told obesity is on the rise - globally. But if you think about it, how often do you see an obese chief executive, or tech entrepreneur, or politician even? Especially a female one. Perhaps the reason is because society discriminates against fat people. In this Why Factor we explore why it is OK to be anti-fat, where that attitude comes from, and what it feels like to be on the receiving end of society’s prejudice. Producer: Gemma Newby (Photo: A woman and a man sit together. Credit: Getty Images)

Beauty pageants project an image of inspiring glitz and glamour. Often contestants enter these competitions to boost their confidence and take advantage of the platform they provide. But, there are plenty of critics who argue they objectify women, and are out of place in a world striving for gender equality. In this week’s Why Factor, Sandra Kanthal asks: in an age of female empowerment, why do women still compete in beauty pageants? Presented and Produced by Sandra Kanthal Editor: Richard Knight Audio clips courtesy of: Binibining Pilipinas 2010- Crowning Moment Audio: From Youtube footage Credit: Name: tpageant Virtually Viral – Guys Go Insane over Miss Philippines Audio: From Youtube footage Credit: Name: Virtually Viral Miss Universe 2015 Audio: From Youtube footage Credit: Name: Vevo/Fox Miss Peru 2017 Audio: From Youtube footage Credit: Name: Guardian News Photo: Silhouette of woman holding a beauty queen crown Credit: Getty Images

Instagram’s one billion users love architecture. If you search for #architecture, you will get hundreds of millions of results. Some architecture publications have more followers than household names like Cosmpolitan for example. We also seem to love to use buildings as a backdrop to our own vanity, as the number of selfies on Instagram proves. But if architecture is so popular on the platform, does that mean that architects are now starting to design our buildings and public spaces to be Instagrammable? Australian architect Scott Valentine tells us that is increasingly what clients are asking for. So much so, he’s created an Instagram design guide for architects. Carl Turner, who is behind the new multi-use building called Peckham Levels in London, which is also very popular on the app, says that Instagrammability was on the clients’ brief. We also hear from architect Ippolito Pestellini Laparelli, who works for Rem Koolhaus’s Office of Metropolitan Architecture. He is worried how the need to be always be on social media affects up-coming architects. Travel writer Helen Coffey explains how cities are exploiting Instagram to attract visitors with installations and space design – from big, signature pieces like Thomas Heatherwick’s Vessel in New York to fairly crude attempts featuring temporary pastel walls with fake flowers and large letters spelling a city’s name. But it is not just conventionally pretty and shiny that catches the eye of Instagrammers. St Louis photographer Demond Meek became popular with his haunting photos of dilapidated houses in his city. He credits the immediacy of the platform for getting him out of a creative rut. Art and architecture historian Philip Ursprung points out that photography and architecture have a long, common history, but also warns that many new cities are increasingly created to look good on photos and from afar, but are out of proportion and unpleasant to be in. Presenter: Ivana Davidovic Producer: Rose De Larrabeiti Editor: Richard Knight Image: Monster Building (Quarry Bay) Hong Kong Credit: Getty Images

The concept that you can get ahead on your work and talents, also called meritocracy, is something we mostly agree is good. We also equate it with a fairer society, one where the social order is not determined by birth but one which gives us some sort of agency over our futures. However the term itself was coined as a warning. So why do we believe in it so strongly? The sociologist Michael Young first used the term to describe a dystopia where believing in meritocracy would legitimise inequality. We speak to his son, the journalist Toby Young, about his father’s and his own views about shortcomings of meritocratic societies. We hear from schoolgirls in inner-city London who question meritocracy, but are determined to get ahead in the world regardless. Entire cultures and societies are formed around the concept of meritocracy. Psychology Professor Shannon McCoy tells us about the American Dream and how buying into it can alter people’s well-being, and Prof Ye Liu tells us about the civil servant exams of ancient China and the country’s current relationship with meritocracy. Finally the author Anand Giridharadas cautions us about buying into this concept and gives us the view from both India and Silicon Valley, and consultant Joelle Emerson talks about how she tries to help tech companies in California hire more diverse workers. Presenter: Nastaran Tavakoli-Far Producer: Ivana Davidovic Editor: Richard Knight

We live in a world where going fast – and faster – is an everyday fact of life. Where fast cars, fast boats and fast athletes command our attention. In theme parks we queue for the most fastest, most exciting rides. But why do we find speed so thrilling? Caz Graham meets people who risk their lives to set world speed records, the boss of a Formula One race team, and a sports psychologist to ask – why are we so taken with speed? What motivates people like Formula 1 or speed boat drivers to stretch themselves to the limits of what might be dangerous? Do we like scaring ourselves? Caz visits the annual Coniston Power Boat Records Week in the English Lake District to meet the teenager who hopes to break a world water speed record and she hears of the risks that going at speed on water can entail. She hears from a ‘thrill engineer’ about why people like to ride roller-coasters. From the psychologist who worked with the UK’s Olympic cycling team in 2016, Caz hears what it takes psychologically to be able to want to go faster and faster. And from the man in charge of Renault’s Formula One team she discovers the engineering effort that goes into designing fast cars – and what it takes to be the driver of such cars as they race around high speed tracks. (Photo: Zapcat powerboat racing, Fistral Beach, Newquay, Cornwall, UK. Credit: Education Images/UIG/Getty Images)

When things go wrong, we crave something or someone to blame. It’s a strategy which puts people on the defensive, and can create a toxic culture. People remember when they have been blamed for something, and will be quicker to deflect blame themselves. It’s a primitive emotion which can be found in almost every society. In this edition of the Why Factor, Sandra Kanthal asks: why do we play the blame game? Contributors to this programme include: Mark Alicke, Psychology Professor, Ohio University Terri Apter, Psychologist and Author of Passing Judgement: The Power of Praise and Blame in Everyday Life. Charlie Campbell, Author of Scapegoat: A History of Blaming Other People Dr Cicely Cunningham, Oncologist and founder of the campaign: Learn Not Blame Richard Gowthorpe, Criminal Defence Lawyer Armele Philpotts- relationship and family therapist and member of the British Association for Counselling and Psychotherapy. Image: Pointing Fingers Credit: Getty Images

The number of smart speakers in US households has increased by 78% year-over-year, from 66 million in December 2017 to 118 million in December 2018. About ten million people in the UK now use one and, on average, one in 10 people in the world now own a smart speaker. And it does not seem like the rise is stopping any time soon. Presenter Paul Bakibinga investigates the current possibilities of a smart home and voice design. Together with experts he explores how owning a virtual assistant - always on and always listening - introduces a whole host of issues to consider - from privacy through to child development and rampant consumerism. But, using your voice for browsing the internet, playing music or ordering groceries has proved to be a lifeline for disabled and elderly users. We hear from child psychologist Rachel Severson, online privacy expert Florian Schaub, computer voice expert and psychologist Jonathan Gratch, Google’s Cathy Pearl and the author of Radical Technologies Adam Greenfield. We are also invited to a multi-generational home of smart speaker users who don’t all agree whether these machines are a force for good or another way of surrendering our privacy. Presenter: Paul Bakibinga Producer: Ivana Davidovic (Photo: Smart Speaker. Credit: Getty Images)

A present connects, communicates and makes people generally happy. It can strengthen a relationship, but also jeopardise it. Have you ever wondered why a certain present was chosen for you? And how much thought goes into the presents you give? This Why Factor unwraps the social complexities that surround the giving of gifts. Lore Wolfson finds out what makes a perfect present and receives clues on how to choose it. While revealing the risks inherent to the act, especially when a gift is given across cultures, she also learns why it’s best not to give a clock to someone from China and seeks advice on the pitfalls that need to be navigated. A psychologist uncovers some underlying motivations of why we give presents and shares tips on dealing with disappointing ones. The truth about gifts – donated free and without obligation – in the Why Factor. Presenter: Lore Wolfson Producer: Sabine Schereck Editor: Andrew Smith Picture Credit: Getty Creative / iStock / AntonioGuillem

In a world increasingly obsessed with health, the fitness technology market is booming. Whether you’re a serious athlete or just enjoy a casual run or cycle around your local park on a Sunday morning, it seems more and more of us are using fitness devices and activity trackers to record our efforts. But what is the motivation for measuring every aspect of a workout? Can it inspire us to go further, faster or longer? Sharing our performances online allows us to compete virtually with pretty much anyone across the globe – but does it risk turning every training session into a race? Presenter Lowri Morgan talks to the CEO of one of the most popular activity trackers Strava which has more than 36 million members. James Quarles says the main reasons why people use these apps and devices are motivation, competition and simply recording your efforts. But in South Africa in the township of Soweto, the local cycling club is using the data from activity trackers to try to persuade sponsors and professional cycling teams to take on their best riders. They say the statistics help back up their claims about the potential of a rider. While for many these devices and apps are a great help in motivating us to exercise, for some they can increase the risk of exercise addiction. Sport psychologist Dr Josie Perry says athletes can do many more miles training than is necessary simply because they are chasing an online challenge. Lowri meets cyclist Ben Dowman from the UK who says in the past he became somewhat obsessed with trying to top the leader board on his activity tracker – even monitoring the weather to know when the wind direction would be most favourable to beat his rivals’ times. As more of us record every step, pedal stroke and heartbeat, these apps and devices are changing the face of exercise as we compare, share and compete online. Presenter: Lowri Morgan Producer: Paul Grant Editor: Gail Champion (Photo: Female cyclist points to a smart watch on her wrist showing heart rate./Photo credit: ipopba\Getty )

Whether it’s climbing Everest, hiking through the Amazon jungle or cycling round the world, why are more of us taking on extreme endurance challenges which push our minds and bodies to the limit? Marathons now seem commonplace and a whole new breed of extreme events have come along such as the double, triple or even Deca Ironman, sailing thousands of miles alone, multi-day adventure races and activities that defy description. Presenter Lowri Morgan spends much of her time seeking out these adventures and extreme challenges. She is an ultra-runner and has raced 350 miles non-stop across the Arctic Circle and run through the Amazon jungle. She talks to other runners about what motivates them to tackle such long distances, often in extreme conditions. We hear from one competitor racing in the Himalayas who started taking on endurance challenges after a difficult time in his life. Another runner who is attempting to get the record number of ultra marathons in a year and run a thousand marathons in four years, says he has yet to celebrate any of his achievements. According to experts, the main motivation for competitors is to test themselves to the limit and to set and achieve a goal. Endurance athletes appear to have a higher tolerance to pain than the rest of us and a more positive mood, not only after a race but during their daily lives too. But there can be downsides. There’s evidence that endurance athletes – in particular runners – have a much higher chance of exercise addiction which can impact on their health and family life. But for many, the satisfaction they feel when they have completed such an extreme event means they soon come back for more. Presenter: Lowri Morgan Producer: Paul Grant Editor: Gail Champion (Photo: Endurance athlete Lowri Morgan in training / Photo credit: Lowri Morgan)

We are asking why so many people are fascinated by Zombies. For many people the Zombie is a walking corpse that’s out to bite you, and turn you into a similarly mindless, flesh craving undead person. What’s not to like? And we seem to be going through a bit of a Zombie boom with TV series like The Walking Dead capturing the imagination of audiences worldwide. But Zombies have been around for more than a hundred years. They first came to the attention of the American public through a book called The Magic Island, about Haiti written by William Seabrook in 1929. And we will be exploring why many say there’s more to Zombies than a reliable source of Hollywood horror. Perhaps they tell us something about significant, deep divisions at large in society. We will be tracing their history through the centuries and continents – from Africa through to Central America, the US and Europe. Photo: A man dressed up as a Zombie Credit: Getty Images

Why do some instruments get all the tunes and the respect, while others are left at the bottom of the heap? The leader of the orchestra is always a violinist, and the guitarist usually gets to leap around at the front of the band. Meanwhile other instruments, like the drums, don’t get a lot of attention - except when it comes to being the butt of jokes. Matt Allwright is on a mission to uncover the source of this terrible injustice, and find out whether his own beloved “low status” instrument – the pedal steel guitar – can ever find the spotlight. Guests include: • Stewart Copeland – The Police (drums) • Dr Daria Kwiatkowska – composer, University of Birmingham (piano) • Margaret Birley – Keeper of Musical Instruments, Horniman Museum • Superorganism (assorted) • Richard Farnes – conductor • Stephen Bryant – leader, BBC Symphony Orchestra (violin) • Tony Bedewi – BBC Symphony Orchestra (timpani) • Tomoka Mukai – BBC Symphony Orchestra (flute) • Steve Magee – BBC Symphony Orchestra (contrabassoon)

Wine has been referred to as the nectar of the gods, and has been tempting connoisseurs for centuries. But contained in this simple pleasure is an incredibly complex product; and anyone interested in reaching the pinnacle of the wine world must learn more about what goes into every wine bottle than most of us will ever take the time to know. In this edition of the Why Factor on the BBC World Service, Sandra Kanthal speaks to experts of the wine trade to find out why there is so much to discover from a bottle of wine. Image: Wine being poured (Credit: Getty Images)

It’s a bite in Mexico, a sweetener in Britain, Tea money in Cambodia. Why do we collude with corruption when it’s unfair and costs us billions of dollars? Nastaran Tavakoli-Far examines the moral quandaries we face when asked to pay a bribe. She talks to a whistle-blower, a businessman imprisoned for corruption and experts and ordinary people affected by bribery in different parts of the world. It’s estimated that 1.6 billion people have to pay bribes just to access public services. When so many countries have signed up to fight corruption, why is it so difficult to stamp out? (Photo: Handing over cash. Credit: Getty Images)

We all need a place to call our own. For a lot of men, that place is the garden shed. Going to the shed is sometimes seen as eccentric or strange behaviour. What is it about the space inside those four wooden walls, among the tools and the junk, that men love so much? In this episode of The Why Factor on the BBC World Service, Nastaran Tavakoli-Far tries to understand the special bond men have with their sheds. Sociologists say men go to their sheds to escape from the female and family-dominated home - the only nearby place they can think of as ‘male’. There they can make their contribution to the running and maintenance of the home. Or they may be seeking a place to think and to create great art. In any case, psychologists argue that the shed allows men to enjoy solitude, which is crucial in how they process their feelings and emotions. Men have been socialised into their sheds and their solitude. However, that solitude can become loneliness, which psychiatrists know can lead to significant physical and mental health problems. They go to their sheds alone, and can experience an emptiness if friends and family are absent. Nas learns how the shed is being used around the world to bring men together and help them express themselves. Photo: Gary at his shed.

The horse has been part of human society since earliest times – archaeologists have unearthed evidence from over 5000 years ago in central Asia. Over the centuries, the horse has been celebrated in myths and legend, it has played a role as human society developed, in farming, in warfare and in the industrial revolution. Today’s thoroughbreds are valued in millions of dollars for their potential to win races and massive prize-money for their owners – while owning a pony is the romantic dream of countless young girls. Caz Graham explores the deep connection between horses and humans. She hears the reasons why horses are so much a part of daily life Mongolia, and how the fell ponies of northern England are valued for their capacity to work. For all our shared history, there remains a strong element of mystery about horses. Many people believe in the therapeutic potential of horses but the science behind it remains difficult to pin down. In this programme Caz hears from academics, authors, legendary racehorse trainers, as well as those individuals who love their horses, in order to understand more about the special relationship between the horse and humans. Photo: Alex with one of her horses

Every day we’re bombarded with information and, with each new story or alternative fact, we have to decide what we believe to be true. But some of the mental short cuts we take to sift through this material allow us to be deceived: past experiences, political beliefs and laziness can all cloud our judgment. In this episode of The Why Factor, Sandra Kanthal explores why truth can be elusive. We’ll meet a woman who discovered her husband had been lying to her for 15 years, and fought through her pain to find the truth. We talk with one psychologist who argues that critical thinking skills can be weaponised to encourage a person to believe in conspiracy theories; and to someone who, through extensive research, is convinced the earth is flat. People shape their identities around their notion of truth. This may go some way to explain why it is easier to fool someone than to convince them they have been fooled. Producer: Chris Browning Picture: Goldfish Shark Credit: Getty Images

Fake News - sometimes it’s obvious to spot, other times it requires more thoughtful investigation. That’s a fact checker’s job; dedicated researchers trying to flesh out what is true and what is not in the deluge of information we see every day. In 2015 the International Fact Checking Network was established to give strength to this small but dedicated group. It now has 62 verified signatories. In this episode of the Why Factor on the BBC World Service, Sandra Kanthal speaks with fact checkers from Turkey, the Philippines and Brazil; to find out what motivates them to combat Fake News, especially in countries where speaking truth to power comes with considerable risk. How do they do this difficult job, and why are they so determined to improve the skills all of us can use to call out false claims? Photo: A fact checking journalist at work Credit: AFP / Getty Images

Ayeisha Thomas-Smith discovers how when we suffer a scarcity of mental resources, we fail to plan for our futures. That means, according to Princeton psychology professor Eldar Shafir, that millions of people on low incomes where money is scarce are finding it much harder than others to improve their lives. Not because they are untalented or do not want to, but because their brain circuitry is overloaded. And the professor believes even people who are not short of money but are trying to lose weight, could also be impacted by this scarcity mindset. Ayeisha hears about experiments in the US and India which seem to show that as our mental “band-width” diminishes and we become overloaded by problems, our chances of thinking our way out of our situation reduces as well. (Photo: An Asylum Seeker. Credit: Getty Images)

Why do people love plane, train and bird spotting? Novice aviation geek Alys Harte enters the worlds of twitchers, birders, watchers and spotters. She meets Noel Marsh-Giddings, who has flown on the shortest and longest flights on the planet - just for the sake of flying; she goes ‘birding’ on the east coast of England with Ashley Saunders where they have a close encounter with a sparrow hawk (and a photobombing mallard!) and speaks to Prof. Kiyohito Utsunomiya, transport economist and railway fan about the subcultures within subcultures that make up Japanese ‘tetsu’ train spotters. Photo: Man in a field with binoculars. Credit: Getty Creative Images. ISO3000

Women are increasingly seeking out ways to look after their minds, bodies and emotions. Nutrition and lifestyle changes - from meditating to drinking green smoothies full of so-called super foods - all come under the term wellness. There are wellness celebrities and online communities, observers even refer to a wellness industry. Nastaran Tavakoli-Far asks what is driving women away from the medical establishment in an effort to improve their health. Photo: Yoga Exercise At Wetland In Huangshan Credit: VCG/VCG via Getty Images

Open Secrets - when everybody knows something is going on but it is never officially acknowledged. Things are left unsaid, remaining in this strange unacknowledged state for decades. So why do some open secrets not come out sooner? Nastaran Tavakoli-Far looks at the Catholic church, the trading floor and to the wrestling ring to find out why very different open secrets have continued for so long and why they eventually came out. Presenter: Nastaran Tavakoli-Far Producer: Clare Spencer Photo: Cassius, wrestler in ring Credit: Alistair Veryard Photogaphy

Rhetoric has been described as the art of persuasion. Used to its best effect, it can make what you say very convincing. In the age of non-stop tweets, news updates and digital distractions, discourse feels like it’s become more immediate, less considered and, often, more aggressive. What should be reasoned rhetoric now often deteriorates into the quest for the perfect putdown. In this week's Why Factor, Sandra Kanthal finds out why, in the age of the 280 character polemic, it could be useful to learn more about the ancient art of rhetoric, and how this is yet another arena where machines may have an advantage over humans. Image: A statue of Aristotle (Credit: Getty Images)

We hear about disasters and bad things happening in the world around the clock. Thanks to our TVs and smartphones we are bombarded 24/7. And charities use those same platforms to appeal to us for donations almost as frequently. Those whose job it is to care – doctors, nurses, mothers even – face even more relentless demands on their compassion. Until one day some feel they cannot go on anymore. We are all vulnerable to compassion fatigue – whether we are unable to deal with more bad news, or to care for our patients and children. But why do we get it? Why do we stop caring? And what is the impact on society when people just switch off and tune out? Photo: Overwhelmed by the demands made on us. Credit: Getty Creative Images

You’re a feminist. You’re pregnant. It’s a boy. What next? Feminist mothers share with Nastaran Tavakoli-Far the complexities of bringing up a son. One mother feels she has failed to impart her feminist values to her 17-year-old son who insists on listening to songs with misogynistic lyrics. Another mother confesses that she is conflicted - on the one hand she thinks men have had their turn at the top of society and now they should keep quiet. On the other hand, she wants her 15-year-old son to be heard. On the son’s side, Nastaran talks to a man who says he couldn’t trust his mother has his best interests at heart because she was a feminist. He felt so strongly about this that he set up a political party to assert men’s rights. And then there are the men who have benefited. Research shared with Nastaran puts forward a surprising finding – that men now feel more loved by their mothers. Nastaran hears from a 25-year-old who says he can share everything with his mother. In contrast, research shows that men brought up in the 1950s said they couldn’t open up and be affectionate with their mothers because of the masculine culture that dominated before feminism. Image: Young son hugging his pregnant mother. Credit: Science Photo Library

Fathers can influence their sons long after the two have stopped living together. The father can act as the role model or, conversely, a cautionary tale. In this edition of the Why Factor, Nastaran Tavakoli-Far talks with fathers and sons about how the relationship has affected them profoundly. Image: Honduran Father and Son. Credit: Getty Images

Have you ever been captivated by a book, full of stories you never knew, revelled in that new knowledge …and then forgotten it all? If the answer is yes, take heart; you are not alone. Why is it we remember some facts easily, and others slip away? In this week’s Why Factor Sandra Kanthal asks why do we forget the things we’ve learned. Image: Brain Concept. Credit: BSIP / UIG via Getty Images

Heartbreak after love lost has been written about for generations. Who can forget the tragic love story of Romeo and Juliet? Or how Rose lost Jack in Titanic? Some of our favourite songs were inspired by heartbreak and as most of us have felt heartbreak in one form or another, relating to their words comes easy. But what causes these feelings? Is it all a figment of our imagination prompted by our society and culture or is there more to it than that? Can we fall sick or even die from a broken heart? And what does science have to say about it? (Photo: Broken Heart. Credit: Getty Images)

Why would you go to the coldest place on Earth? A place mostly devoid of life, where there are rarely more than a few thousand other humans spread out across a landmass twice the size of Australia. A place whose sublime beauty is matched by its capacity to kill you, very fast. We are talking about Antarctica. A continent which belongs to no nation has no government and is run according to an international treaty signed nearly 60 years ago. Shabnam Grewal went there many years ago and knows the joy of being surrounded by ice blue glaciers and the hardships of working in a freezing climate. She talks to others who were drawn there too, by the beauty of the place or in search of knowledge or to test themselves and understand who they really are. (Picture: A Freediver in Antartica, Credit: Freedive Antarctica / Barcroft / Barcroft Media via Getty Images)

Boredom is a powerful emotion, one which many of us will go to lengths to avoid. Psychologists describe its purpose as trying to get us to do something else. Boredom can spur us on to do something more meaningful, or tempt us into dangerous behaviours. In this edition of the Why Factor, Sandra Kanthal talks with researchers who think boredom is anything but boring. Image: A bored woman behind a rainy window in a tram, (c) Getty Images.

Lesley Curwen has sailed thousands of miles around Europe on her yacht and knows the strange joy of being out of sight of land. Talking to fellow sea-lovers - sailors, a marine biologist, an artist and a Captain of a merchant ship - she asks why we are drawn to go to sea and put ourselves at the mercy of wind and waves. Is it a yearning to be close to nature, a test of self-reliance or can science explain why our brains are attracted to the ocean? Photo: The sea. Copyright Shutterstock

Why do so many of us love boats? They are used as homes as well as for work and pleasure across the world. Lesley Curwen, a proud owner of a yacht, finds out how our love affair with the boat can be a deep, passionate attachment and how some vessels can take on the character of their owners. In some cultures boats are seen as living things and the best place to create family memories far from the busy, connected world of dry land. (Photo: A boat on the sea)

Just like in the TV show Sex and the City, female friendships tend to be uniquely close – women talk often and share a lot. But this level of intimacy can make the relationships susceptible to serious and even terminal breakdown. As friendships increasingly take place through social media, Nastaran Tavakoli-Far looks at why new technology can be a mixed blessing for female friendship by exaggerating existing vulnerabilities yet enabling increased connectedness. She also learns why it’s a particular problem for teenagers as well as how a mutual admiration of One Direction can be the bedrock of a good friendship. (Photo: Three Female Friends. Credit: Shutterstock)

From the Obama-Biden bromance to the transformative experience of the men’s group, Nastaran Tavakoli-Far explores what men can get from their friendships with other men that is unique. With theories from Aristotle to the modern day, she looks at how long held notions of masculinity sit within redefined gender roles and can prevent men from getting close to other men. And also learns about the importance of music in making friends and why being able to show our weaknesses is so crucial to forming friendships. (Photo: Joe Biden and Barack Obama. Credit: The White House)

Why do people go to their school reunion? Caz Graham goes to a 50th anniversary school reunion in the North of England where she meets people who are encountering friends who have not seen each other for years. She hears how the event prompts their memories of school days from the 1960s and also what they have done in the years since leaving school. Caz explores the strength of feelings that school day memories produce and finds out from experts why these enduring memories draw people back to reunions. She hears from Professor Vered Vinitsky Seroussi about the importance of being able to recount what has happened in our lives to those who were our first friends during school days. The benefits of attending a school reunion are explained by Professor Jerome Short. School reunions happen around the world and can start just a few years after leaving school – Jen Bilik has attended four reunions, starting with the tenth anniversary and explains how her attitude towards them changed over the subsequent years. She explains how attending a school reunion is a way of taking part in a longitudinal study of our lives. (Image: School Reunion. Credit: Shutterstock)

Dividing people into groups is part of our social experience. Be it through race, gender, nationality; we build our identities through groups we belong to. And these identities can be numerous and elastic. But, what makes us decide who is like us and who is the other? In this week’s Why Factor, Sandra Kanthal asks; why do we divide the world into us and them? (Image: Baseball caps, Credit: Sandra Kanthal/BBC)

How often do you think about other peoples’ opinion of you? In many parts of the world status is something we can change through education, occupation and wealth but what if you come from a culture where the status you are born with is inescapable? We speak to author Sujatha Gidla about growing up as one of India’s Untouchables: the outcasts of the country’s rigid Caste system. Lifestyle and fashion blogger Sasha Wilson shows us how high the status stakes are in the completive online world of Instagram. And is the pursuit of status bad for our mental health? Professor Richard Wilkinson believes so and argues that the bigger the gap between rich and poor the greater our obsession becomes with it. Finally, is status something we can just buy? Brian Hamilton runs a business selling Scottish noble titles to the highest bidder and so presenter Priscilla Ngethe considers becoming Baroness of Pentland… (Field recordings of the Shuar Ecuadorian Indians thanks to Mike Woloszyn and freesound.org) Image: John Cleese, Ronnie Barker and Ronnie Corbett in the Class Sketch from Frost Over England, 1967 (Credit: BBC)

People have been fishing for thousands of years – it is one of the last hunter gatherer activities. But increasingly it is becoming more difficult, as fish stocks dwindle or regulation limits the number of fishes that can be caught. Caz Graham asks why do people continue to fish despite these difficulties. She goes out into the Solway Firth in the north of England, with a group of haaf net fishers who use a traditional form of salmon fishing that dates back over a thousand years. She hears how new regulations have limited the number of fish that can be caught – something that the fishers say could threaten this form of fishing. To find out more about how people continue to fish internationally, we hear from a fishing community in Alaska, and about tuna fishing in the Maldives. On the North East coast of England, we meet a fishing party as they complete successful day’s fishing from the tiny harbour of Staithes – and further along that coast, we hear from a trainee at the Whitby Fishing School who explains why he wants to join the fishing industry. Professor Calum Roberts of York University in the UK explains the motivation behind fishing and the changing character of fishing today. (Image: Old fisherman with nets, Credit: Shutterstock)

Why has football becomes the world’s favourite team sport? Aasmah Mir asks why “soccer” has developed such a huge following. As the FIFA World Cup kicks off in Russia, Aasmah talks to players and fans across the world about the game’s accessibility, simplicity and unpredictability. (Image: Children playing football on beach, Credit: Shutterstock)

What is it about a beautiful landscape that people like so much? Caz Graham explores the appeal of landscapes, starting with a visit to the English Lake District and the site of William Wordsworth’s poem, Daffodils. Caz meet local poet Harriet Fraser and her husband, photographer, Rob Fraser, to hear what it is about the lakes and mountains where they work that so inspires them and other artists. She meets high altitude mountaineer Alan Hinkes to find out why he is drawn to wild and potentially dangerous mountains. And she meets day-trippers who are drawn back again and again to take in the classic Lake District vistas. Professor Catherine Ward-Thompson, an expert in landscape architecture at Edinburgh University in Scotland explains the connection we feel with landscape and the theories that seek to explain it, including the potential therapeutic value of being part of the landscape. Hitesh Mehta, a landscape architect who specialises in eco-tourism, explains how different cultures feel a connection to their landscape. The black and white photographs of Ansell Adams of the mountains of Yosemite and the deserts of New Mexico in the USA are classic images of these landscapes - his biographer Mary Alinder tells Caz why these places meant to much to Adams. (Photo: A green valley and hills in the horizon)

Why do we believe complete strangers can guide us in improving every aspect of ourselves. Mary-Ann Ochota explores whether the self-help industry really changes peoples’ lives. Mary-Ann visits a self-improvement workshop, talks to the owner of an Indian finishing school and to two academics who spent a year in bitter competition as each attempted to outdo the other in self-improvement. (Image: Yes you can, Credit: Shutterstock)

Why do we have such a close and complex relationship with dogs? No matter whether you love or hate them, it’s undeniable they’ve built up a special relationship with us that most animals haven’t. On this episode of The Why Factor, we find out why dogs are so special. Mary-Ann Ochota delves into the emotion, science and history that sets them apart - be they friend, foe or food. (Image: Essex Search and Rescue, Credit: Gabriela Jones/BBC)

Although we don’t like thinking about it, most of us are resigned to the fact that we won’t escape death in the end. But there are people who have dedicated their entire lives to conquering death. This relatively new movement of so called ‘transhumanists’ believes that science is close to finding a cure for aging and that immortality may be just around the corner. Chloe Hadjimatheou asks why some people chase immortality. (Image: Theatre, Credit: Copyright ©2018 Alcor Life Extension Foundation)

Why do people marry themselves – and what even is self-marriage? The Why Factor meets the self-married, who argue if marriage is about committing to an individual - to love and cherish, in sickness and in health - who better to commit to… than yourself? Mary-Ann Ochota finds out why this emerging phenomenon is so popular amongst women in particular. And why self-marriage can be either a radical act of self-love, or the ultimate cosplay. And sometimes both. (Image: Grace Gelder, Credit: Amy Grubb)

Why do people fall for online romance frauds? With false online profiles, doctored photographs, and convincing background stories, online fraudsters target people who are looking for love and online relationships. Once they have hooked their victims, they set about stealing money from them. But what convinces people that their new relationship is so realistic that they become willing to hand over large amounts of money to someone who they may never meet. Shari Vahl explores why people fall for such frauds, hearing the stories of two women and the online relationship they believed would bring them a new future – and which turned out to be an costly false hope. Shari hears from cyber-psychology expert Monica Whitty and people hacker Jennifer Radcliffe, as well as from police in the UK and USA. What are the hooks that these international criminal gangs use to defraud their victims and what happens when victims discover that the truth about their online relationship. (Image: Internet dating gone wrong, Credit: Shutterstock)

Why are we giving away our personal data so cheaply and with so little thought? Aasmah Mir asks if it is too late to secure our information. And if it is, whether we should charge for it. She talks to a law professor who believes everyone now has sensitive facts or preferences recorded on what he calls a “database of ruin”, a journalist whose details were revealed after she joined an infidelity website and an entrepreneur who is trying to help people make money by advising them on how to sell their personal data. (Photo: Woman on laptop. Credit: Shutterstock)

In the USA, those least likely to become victims of gun violence are the most likely to carry guns. So if they are not likely to become victims of crime, what are they really afraid of? We speak to people getting their gun licence to try and untangle what lies behind their anxieties and discover it’s about something much less tangible. Presenter: Aasmah Mir Producer: Phoebe Keane Photo: Maria Mathis with her gun on her ranch in Texas, USA, Credit: BBC)

We all fantasise from time to time – about landing our dream job, finding our perfect partner or moving into our ideal home. But some people go much further, creating new personas and elaborate fantasy worlds that become central to their lives. Nicola Kelly finds out why, spending time with cosplayers, delving into the virtual world of Second Life and visiting the nightclub where people explore their sexuality by dressing as unicorns and dancing to trance music. (Image: Human unicorns in parade, Credit: Shutterstock)

Why do so many people decide to open a restaurant? Mary-Ann Ochota speaks to the people who have been through the joys and stresses of serving fine food around the globe, those who are just embarking on the journey, and those who are exploring new and modern ways to serve food. However, according to Restaurant Consultant Linda Lipsky, a majority of restaurants fail in their first year. So why do so many people still dream of opening a restaurant when the odds are stacked against them? Can the reality ever match the fantasy? And why are so many people willing to risk it all to chase their dream? Presenter Mary-Ann Ochota Producers: Priscilla Ng’ethe & Chloe Hadjimatheou (Image: Restaurant Interior: Credit: Shutterstock)

Shivaani Kohok explores why so many people feel that the order in which we are born shapes our character and destiny. Whether you’re the eldest, the youngest or a middle child can make a difference to how we see ourselves and how we relate to others, according to psychologists. And some studies suggest that there economic and educational advantages to being the first or later born child – depending where in the world you live. Herself the eldest of three, Shivaani talks with other sisters of different ages to find out why they love or hate their place in their sibling hierarchy. (Image: Siblings of different ages, Credit: Shutterstock)

Machines are merging into our lives in ever more intimate ways. They interact with our children and assist with medical decisions. Cars are learning to drive themselves, data on our likes and dislikes roam through the internet. Algorithms can determine who gets government assistance and help suggest our romantic partners. But machines learn from the instructions humans give them. So, how do we know that the technology we are creating is going to do the right thing? In this week’s Why Factor, Sandra Kanthal asks if now is the moment we need to think about machines and morals? (Photo: Human and Robot hands, Credit: Shutterstock)

Laziness, slothfulness, idleness and apathy are used as criticisms and insults against individuals, groups and sometimes whole countries. But why? The Greeks saw laziness as a virtue and something to be sought after whereas today we look down on being unproductive. Should we keep ourselves constantly busy or is laziness something we should feel less guilty about? Isn’t a little bit of downtime good for the soul? After all, do good things not come out of taking it easy? (Photo: Legs extended on a hammock. Credit: Shutterstock)

Have you ever wondered what goes on behind closed doors at a men only club? Maybe you have even asked yourself why segregated groups still exist. According to sociologist Todd Migliaccio, society has historically been male dominated making men only clubs suited to the running of it. However, with the current drive towards gender equality and movements such as MeToo and Time’s Up, it begs the question; Why men only? Presented by Afua Hirsch Produced by Priscilla Ng’ethe (Photo: David Staples at the United Grand Lodge in the Grand Temple Credit: Priscilla Ng'ethe)

They roamed our planet for millions of years before most of them were wiped out. So what’s our fascination with the dinosaur? And will our love affair with them endure? Not only is this reptile beast loved by children across the world but it also fires our imagination and has become part of our popular culture, as well hooking us into science. Mary–Ann Ochota talks to Professor Paul Barrett, Natural History Museum, London about the history of the dinosaur; Dr Laverne Antrobus on why kids love this creature so much; Dr Ben Garrod, a self-confessed dinosaur Geek; Randy Kohl who has collected over 10,000 Dinosaur toys in his 63 years as well as Serena Korda, an artist inspired by the dinosaur. Presenter: Mary-Ann Ochota Producer: Smita Patel (Photo: Two dinosaurs fighting each other Credit: Shutterstock) Credit: “Apeing the Beast” music by Grumbling Fur (aka Alexander D Tucker and Daniel O’Sullivan)

Why do bullies do what they do? Shivaani Kohok explores the reasons for bullying behaviour. She talks to two bullies who explain why they do what they do – in one case, a young woman realised how the online comments she had posted about others who had previously bullied her were in fact another form of bullying behaviour. Shivaani talks to experts who provide insight into the different types of bullies including "victims" and "ringleaders". She investigates cyber-bullying, bullying in the family, as well as workplace behaviour where bullying bosses can turn on their highest performing managers. (Image: Child being bullied, Credit: Shutterstock)

Job interviews are stressful experiences and have mostly been proved by scientists to be ineffective at selecting the right candidates. So why has this means of selection survived so long and why is so much value placed on it? Catherine Carr explores the cultural and psychological bias that flaws them, how we might improve the experience both as interviewee and interviewer, and the extent to which technology might hold promise in making the process fairer. (Image: Someone at an interview, Credit: Shutterstock)

Pain comes to us all at some point in our lives. Sometimes it’s a short, sharp shock. Other times, it seems to cling to us. A person’s pain is a unique experience and describing what hurts is not a simple task. In this edition of the Why Factor on the BBC World Service, Sandra Kanthal asks why we need to understand more about pain and learns more about new ways being developed to manage and measure pain. (Photo: Pain level meter indicating maximum Credit: Shutterstock)

Curing phobias, managing pain, entertainment: hypnotism has a number of tangible benefits. But it can also carry significant risks for the most suggestible people. So why would anyone allow a stranger to access their mind? Nicola Kelly speaks to performers, dentists and therapists who use hypnotism in their work and discovers how the brain functions when in a trance. Through hypnosis, she faces her own fear of rats, hears from a patient who had his front tooth extracted without anesthetic and witnesses colleagues convinced they are Donald Trump. But does the hypnotic trance really exist? Sceptics explain why they no longer believe it works and set out the hidden dangers. Presenter: Nicola Kelly Producer: Chloe Hadjimatheou (Image and Credit: Ben Dali)

Why are more and more people giving up all food produced from animals? Mary-Ann Ochota explores if it’s natural for us to eat meat, and the impact on our health and the environment. She looks at how social media is helping spread the vegan message, the pros and cons of a solely plant based diet and whether eating meat today is ethical. (Image: Selection of Vegan dishes, Credit: Shutterstock)

Why do some sleep disorders turn normal dreams into terrifying nightmares? And what do they tell us about the workings of the brain? Dreaming usually occurs in REM sleep (Rapid Eye Movement sleep) when our brains are very active, but our bodies are almost completely paralysed. But sometimes, the switch that paralyses our muscles is faulty, causing conditions that can significantly impact our days and nights. Neurologist, Dr Guy Leschziner, from Guy's and St Thomas' hospitals in London, introduces us to some of his patients with problems that include sleep paralysis and hallucinations. We meet Evelyn whose sleep has been plagued by visions so scary, she doesn’t want to go to bed; we hear from Christian who has narcolepsy, a rare brain condition that makes him suddenly fall asleep at inappropriate times. And we meet John who has REM sleep behaviour disorder (known as RBD) which causes him violently to act out his dreams, sometimes injuring himself and his wife, Liz. And we learn how RBD may be an early warning of degenerative brain conditions like Parkinson's disease and certain types of dementia. These disorders arising from dreaming sleep help us to understand why we dream and the role of REM sleep. (Photo: Sleeping woman having nightmare, Credit: Getty Images)

Why high levels of noise affects all of us. David Baker explores how different sounds can impact on people without them even knowing and how to make our lives more tranquil. From the clangs and clatter of city life to weapons that use sound to harm us, noise can be a lot more dangerous than we think. But help is at hand from quieter underground stations to restaurants where the sound changes to reflect our moods and preferences. (Image: Crowded, noisy, station; Credit: Shutterstock)

Meet Rachel Waddingham and meet the voices that inhabit Rachel’s head: there is three-year-old Blue who just wants to play with other children, 11-year-old Elfie who is easily offended and a panel of three critical scientists. Peter hears a voice that dictated an entire children’s book to him. Around 2% of people claim, like Rachel, to be inhabited by voices with whom they have full blown relationships. Are they all sick? What causes people to hear voices? And why have some psychologists changed their minds about the dangers of colluding with the voices? (Photo: Rachel Waddingham)

Why do some of us do bizarre things in our sleep? Like riding a motorbike, using a shoe to ‘phone for pizza or even having sex while sleeping? These are complex behaviours and yet sleepwalkers aren’t aware of what they’re doing and often have no memory of their strange night-time activities. These sleep disorders are known as non-REM parasomnias and include conditions like night terrors and sleep eating. Neurologist, Dr Guy Leschziner, talks to patients he’s been treating at his sleep clinic at Guy’s and St Thomas’ hospitals in London. They include Jackie who began sleepwalking as a child and continued her strange night-time behaviour as an adult, even driving her car whilst sleeping; from Alex who rescues people from floods in his sleep. And we hear from Tom, whose recent diagnosis of sexsomnia has had a significant impact on his life. (Image: Girl on tightrope in moonlight, Credit: Shutterstock)

Catherine Carr asks why excessive drinking can sometimes seem to be socially acceptable. And why countries like America and India have at times turned against alcohol. She hears stories of addiction in India and Kenya and a history of temperance and prohibition movements in America. Medical specialists explain why people can become alcoholics, why some people are drinking more and the treatments available. How Alcoholics Anonymous began and how a new synthetic alcohol may provide a solution. (Image: People drinking, Credit: Shutterstock)

Why have so many women in so many different cultures and eras been denounced as witches? BBC Africa’s Sammy Awami visits a village in his home country of Tanzania where, just four months ago, five women were murdered after being accused of witchcraft. Sammy meets a witch doctor who believes he has met a witch and talks to a local politician who is trying to stop the killings. We also hear from Professor Dianne Purkiss, an expert on the European witch hunts of the Early Modern period. And he travels to Glastonbury in the South West of England to meets a modern-day witch, Liz Williams, owner of the Cat and Cauldron witchcraft shop. (Image: Villagers in N. Tanzania where people have been accused of being witches, Credit: Sammy Awami/BBC)

When a group of people come together, they form a crowd. Strangers connect and share a common purpose and identity. It's an exhilarating experience. At football matches, music festivals and protest marches, people become energised in groups. They can be frightening places when they erupt in violence, or peaceful forms of protest when we try to change social norms. In this edition of the Why Factor, Sandra Kanthal asks why we take courage from a crowd. (Image: Large crowd of people, Credit: Shutterstock)

Coming of age rituals, hazing at universities or entrance rites into secretive organisations, initiations are present in every culture around the world. They are often secretive and can involve horrific ordeals and yet people are still prepared to put up with the pain. So why do we need them and what happens if they are absent? Rhianna Dhillon talks to young men in South Africa who’s coming of age circumcisions went horribly wrong, learns about the inner workings of gang initiations and the mysterious rites held by the elite Skull and Bones organisation. She discovers that however harmful the initiation ceremony, it almost always serves a valuable purpose. Image: People holding hands around a fire, Credit: Getty Images

Professor James Tilley finds out what we can learn about politics from the power struggles within chimpanzee groups and how our evolutionary past affects the political decisions that we make today. Interviewing primatologists, evolutionary psychologists and political scientists, he explores the parallels between our political world and that of other primates. These include the way politicians form coalitions, how people choose leaders, loyalties to parties and even how, and when, we go to war. These similarities to other primates reflect our evolutionary heritage and the way in which stone-age human groups settled disputes internally and externally. (Photo: A female chimpanzee yawns as two others nod-off, while they sit on rocks in a family group, at Taronga Zoo, Sydney. Credit: Getty Images)

Beliefs about language and gender are everywhere; we are told that women apologise more, men interrupt more, women talk more, that men are from Mars and women are from Venus. But are any of these things true? Why do so many people believe them? Catherine Carr speaks to leading linguiss Deborah Cameron and Janet Holmes, who have studied thousands of conversations and gathered data to discover the truth. She also interviews one of the most senior women in technology, Nicola Mendelsohn from Facebook, to discover how stereotypes impact women in leadership roles. (Photo: Donald Trump listens behind Hillary Clinton as she answers a question Credit: Reuters)

Rhianna Dhillon finds out why so many films are dubbed into another language. She discovers the artistic, social and political reasons why countries like Italy, France and Spanish speaking countries have opted to dub rather than subtitle movies. Why it’s still a controversial issue in the Indian film industry. And she takes advice from Dietmar Wunder, the actor who voices James Bond in German, as she tries her hand at the art herself. (Photo: Actress dubbing documentary. Credit: Getty Images)

Millions of people every year visit sites of death, tragedy and destruction, from nuclear disaster zones to genocide memorials. Why do we go? Is it an effort to understand the darker parts of our history, or are we just indulging our morbid curiosity? Mary-Ann Ochota becomes a dark tourist herself to try and find out, visiting the former Nazi Concentration and Extermination Camp Auschwitz-Birkenau in Poland. She also goes to Grenfell Tower in west London, the scene of a deadly fire that tore through a residential apartment in the summer of 2017. Since the night the fire started, people with smartphones congregated to capture the moment and they are still coming. Mary-Ann speaks to local residents to find out about the impact and ethics of their visits. We also hear from Peter Hohenhaus, who is perhaps the ultimate dark tourist, having visited around 700 dark sites all over the world. (Image: Teenage tourists at Auschwitz, Credit: Getty Images)

Have you ever felt like a fraud? You think that one day your mask will be uncovered and everyone will know your secret. According to psychologists, this is a common feeling that many of us suffer from and it has a name; Imposter Syndrome. The term was coined by two American psychologists, Dr Pauline Clance and Dr Suzanne Imes, in 1978. Dr Clance and Dr Imes first thought the feeling was only experienced by high achieving women, but quickly found that men experienced it too. According to subject expert, Dr Valerie Young, women are more susceptible to imposter feelings because they internalise failure and mistakes- whereas men are more likely to attribute failure and mistakes to outside factors. However, those who belong to minority groups of whom there are stereotypes about competence also commonly experience imposter feelings. If you suffer from imposter syndrome, don’t worry you’re in good company; Maya Angelou, Robert Pattinson, Meryl Streep, Viola Davis and many more successful people have expressed feeling like imposters. Presented by Afua Hirsch Produced by Priscilla Ng’ethe (Image: Puppet and mask, Credit: Shutterstock)

Serial killers and their terrible high profile crimes have spawned a massive global industry... feature films, documentaries, TV series, books, magazine profiles, hit podcasts and video games. But why do many of us find serial killers so intriguing? Is it their psychology or the gory details of their murders? Becky Milligan explores the dark world of the serial killer and asks if any of us could be one. (Image: Dark city alley, Credit: Shutterstock)

Inhaling and exhaling – we all do it. No breath means death. So why restrict it? And how does holding our breath affect our bodies and minds? Some argue holding your breath is a good way to manage stress. But what happens when small children do it unconsciously? Lucy Ash goes in search of her inner dolphin, as she finds out why people hold their breath. (Image: Athlete breath holding underwater, Credit: Shutterstock)

When Hurricanes’ Harvey and Irma made landfall in America, hitting Houston and Florida respectively, people who lived in the predicted paths of these devastating storms faced an agonising choice – should they leave their homes or stay put. The Authorities and news media were warning people about the dangers of the storms, yet despite that some people decided to stay. Shivaani Kohok asks why, when natural disaster is imminent, do some people decide not to leave? The reliability of warnings about the storm – and previous experiences – explains why some people do not heed official advice or instructions, according to Judith Fox, from the University of Denver, Colorada. On the slopes of Mount Etna, Chiara Vigo has a vineyard which in 1981 was almost destroyed by a fast-moving eruption – the lava flow stopped metres short of the property. She explains why how she and her husband have restarted wine production – and how the family feel about living and working on the slopes of an active volcano. They have no option but to stay put. (Image: Florida prepares for Hurricane Irma, Credit: Getty Images)

Why is living space important and can we learn to live with less of it? Why are the Japanese so good at living small and is sharing space more important than having space to ourselves? To find out why, Catherine Carr meets the principal investigator on the HI-SEAS project; a specialist in Japanese compact homes; a housing expert; the owner of a Tiny House; a man who grew up in slum; an environmental psychologist and an anthropologist. (Photo: Inside a dolls house. Credit: Shutterstock)

Why would any woman choose to carry a baby for a total stranger? Modern medicine has enabled the childless to have a baby that’s blood-related, by using another woman to carry the pregnancy to term. But what does it feel like to hand over a child that’s been growing in your womb? And should money be involved? Some people condemn surrogacy as a dangerous industry that exploits the vulnerable. Others see it as a welcome solution to the heartache of infertility. Mary-Ann Ochota explores the emotional and ethical complexities of surrogacy and meets women from around the world who’ve chosen to give birth to babies for others. (Photo: Nadine, Credit: Nadine Burger)

Red roses, romantic dinners and Valentine’s Day might have become the modern expression of Romance – but where do its ancient roots lie? And do traditional ideas about Romance conflict with today’s experience of gender, love and sexuality? Afua Hirsch talks to Eddie and Justin Outlaw about their experience of Romance as a gay couple in America’s deep south. We also hear from Kiru Taye, a Nigerian author who wanted to challenge the predominately white and western world of Romance novels; and sex and attachment expert Sarah Merrill describes how the romantic instinct is etched into our very biology. Yet in the world of swipe right, swipe left dating apps – how might our experience of Romance be changing? (Image: Book, heart pages, Credit: Shutterstock)

When we meet someone and ask them what do you do – what are we really hoping to find out about that person? David Baker explores why we ask ‘what do you do?’ and finds out what happens when you decide you won’t start a relationship with a question about work. Why do we believe that our jobs are the most profound thing about us when there are so many other things we could be talking about? What might seem like a simple social convention – a way of breaking the ice – can also reveal a great deal about how much emphasis we place on our jobs as part of our identity. (Photo: Identity branding. Credit: Shutterstock)

Technology has the potential to change all our lives for the better, yet many of us are often reduced to hitting screens in frustration. So why does technology feel so complicated? In this edition of the Why Factor, Kate Lamble explores why we get so exasperated with new technology and whether we should be concerned about increasingly complex solutions to simple problems. Is poor design to blame? Stupidity on the users part? Or is it part of our natural psychological response to artificial devices? (Image: Man hiding under laptop, Credit: Kaspars Grinvalds/Shutterstock)

Many museums around the world hold human bodies and body parts. Egyptian mummies draw huge crowds curious about our ancient past and specimens in medical museums allow us to imagine our own bodies from the inside. Many of these museum objects have become highly contested. Whilst some people may look at them and see artefacts or tools for knowledge, for others, human remains remain human. Shivaani Kohok explores why storing and displaying human remains in museums is so contentious. Many human remains in medical museums were obtained without the consent of the people they were removed from: curators like Carla Valentine of the Barts Pathology Museum in London argue that they should be preserved because they tell a story of the history of medicine, and may still be useful for scientific study. Bob Weatherall has been campaigning for decades to get museums to return remains of Aboriginal Australians to their communities of origin so they can be respectfully laid to rest. Chip Colwell, curator of Anthropology at the Denver Museum of Nature and Science, explains how museums in America have reacted to calls for the repatriation of Native American human remains. Alice Dreger, historian and philosopher of anatomy, believes that museums should consider whether some repatriation claims could result in a loss of scientific learning. J Nathan Bazzel donated his hip bones to a museum after they were surgically removed. (Photo: Barts Museum, Credit: Carla Valentine, Courtesy of Pathology Museum at Queen Mary University London)

News has a powerful pull. We spend so much of our time checking it, absorbing it and talking about it. And some of us even claim to be addicted to it. But why, asks David Baker, do we need news in the first place? So much of what goes on in the world is beyond our control and hearing about it can just make us more depressed. Would we be better off just disconnecting from the news? Or is it part of our civic duty to be informed? And is news really just another form of entertainment – a modern-day version of that basic human pleasure of swapping stories around the campfire? (Photo: Men sit with paper and phone, Credit: Rawpixel.com/Shutterstock)

On trains, in cafes, offices and in the street, we cannot help overhearing conversations not intended for our ears. Catherine Carr explores why we eavesdrop, and whether it is a harmless habit or a dangerous invasion of privacy. The poet Imtiaz Dharker takes ‘furtive pleasure’ in ‘lying in wait for secrets that people don’t even know they’re telling’ and sometimes what she hears ends up in her poems. Canadian journalist, Jackie Hong, eavesdropped on the radio communications of police and paramedics to get the news in real time. Not everything we hear in public is interesting to us: Lauren Emberson devised a psychology experiment to show why we find other people’s mobile phone conversations so difficult to ignore. In some circumstances, eavesdropping can be problematic. The historian Anita Krätzner-Ebert, who works at the Stasi Records Agency, has been conducting new research into cases of neighbours and strangers who eavesdropped and reported on each other in East Germany. Professor of Acoustic Engineering, Trevor Cox explains how some buildings have allowed embarrassing secrets to be overheard and literary scholar, Ann Gaylin says that eavesdropping scenes in novels show writers have always been curious about human curiosity. (Photo: Woman cupping ear, Credit: Dmitro Derevyanko/Shutterstock)

Raising children is demanding. It takes time, money and devotion. So, why would anyone want to raise another person’s child? In this edition of the Why Factor, Mary-Ann Ochota, explores what it means to be a parent. Can mothers who adopt or foster have the same connection to their children as a birth mother would? And, what does it say about human society that we choose to take in the offspring of others? (Photo: Family, Credit: Pressmaster/Shutterstock)

Every country in the world has at least one Sign Language. Each is a complete communication system with its own grammar, lexicon and structure and has evolved over centuries, just like their verbal counterparts. Although many have legal status under disability legislation, only four have been given the status of a recognised official language. But not everyone who is deaf uses sign language, and not everyone who uses sign language is deaf. There is a debate in deaf communities as to whether they have ‘hearing loss’ or ‘deaf gain’ Why do some people view deafness as a disability, while others celebrate it as a cultural inheritance? Some deaf rights campaigners say that Sign language is a signifier of belonging to a Deaf community, with a rich cultural legacy. But does the choice to use hearing aids and cochlear implants to help use verbal language really mean a rejection a deaf culture and a deaf identity – or a practical way to integrate with a predominantly hearing world? (Image: Smiling mother signing with child, Credit: Andrey Popov/Shutterstock) Presenter: Lee Kumutat

We sweat; we feel sick and even shake when we’re faced with the limelight. Our bodies release stress hormones and begin fight or flight response. So why then do some people crave the limelight so badly? Presenter Jordan Dunbar undergoes an experiment to find out what the limelight does to our bodies, to get a chemical answer. We speak with an historian of Fame, Leo Braudy, to hear how Alexander The Great started it all and how he used the Ancient Greek version of twitter to let everyone know how ‘great’ he was. We meet a Celebrity Psychologist, Dr Arthur Cassidy who reveals that attention is hardwired into our brains and how social media get us hooked as well as telling us why we want attention so badly. Star of 52 reality television shows Lisa Appleton knows a thing or two about the limelight, she talks about the main reason behind her search for fame. Rainbow Riots is a group of performers who highlight the injustices happening to the LGBT community around the world. They have come together from some of the most dangerous countries in the world to be gay. Kowa is a performer from Kampala who tells us why she’s willing to risk her life to bring attention to her struggle. George Bamby is an infamous paparazzo, a celebrity photographer who controls the limelight and he tell us what the world behind the camera is like. You’ll never look at the celebrity magazines in the same way again. We’ll find out the reasons behind the obsession with fame and the limelight around the world. Music by Petter Wallenberg and Rainbow Riots (Photo: Presenter Jordan Dunbar performing / Photo credit: Prague Fringe Festival )

Anybody who watched the European Championships of football last summer in France would have seen shocking scenes of violence between fans. The vast majority, if not all, were men. Men also commit more than 90% of murders across the world and are more likely to join a gang. Why are men more violent than women? Caroline Bayley speaks to ex-football hooligan Cass Pennant about his experiences and motivation when violence became his way of life. Former British Army officer Jane Middleton explains the differences between men and women on the battlefield when she served in Afghanistan. And, Caroline also hears views from Sweden about how equal violence between men and women in relationships is. (Photo: Group of football fans fighting in street. Credit: Carl Court/Getty Images)

With increasing numbers of Westerners opting to have smaller families, some go one step further and decide to have no children at all. As a result they often face suspicion, abuse even, for being selfish or materialistic. Women, in particular, who decide to go childless, experience the full force of this near-universal stigma. Mary-Ann Ochota speaks to people who’ve made this often lonely decision. Presenter: Mary-Ann Ochota Producer: Rose de Larrabeiti (Photo: Empty old swings, Credit: Chailuk Chalathai/Shutterstock)

Why do humans kiss? You might think it is a universal trait, something that we all do. But when European explorers travelled the world, they met tribes that didn’t kiss. So is it a learnt response after all? It can be used as a greeting, a sign of reverence or supplication, but we will be talking about the romantic kiss: Face to face, lips to lips. We examine the biochemistry, psychology, anthropology and history of kissing. Where does it come from? Image: Two women kissing at a festival (Credit: AFP/Getty Images)

When many people struggle to maintain one relationship, why do some people enter into multiple simultaneous marriages? Lucy Ash speaks to polygamists around the world to find out why they were drawn to these complex arrangements and how they manage them. Lucy hears about rotas, hierarchies and curfews from the stars of a popular South African reality TV show about a businessman, his four wives and their ten children. The creator of a dating website in Gaza explains why many of his clients are looking for second or third wives. A woman who left her Mormon plural marriage in the American state of Utah tells how having to share her husband with a sister wife had a devastating impact on her mental health. What about polyandry – one woman marrying multiple men? Anthropologist Katie Starkweather explains why some societies have favoured it. (Photo: Models on wedding cake, Photo credit: Shutterstock)

Why do foreign migrants yearn to go home and what happens when they do? Some have had no choice, but others are influenced by nostalgia for their early lives. Or sometimes by disillusionment with their adopted country. When they go back, can the old country live up to their hopes and dreams? Shivaani hears emotional tales from those returning to Jamaica, Sierra Leone, India and Ghana. (Image: Empire Windrush, Credit: Getty Images)

All over the world this summer young people are sitting exams which will have a big impact on their future. In some places, a single exam might determine whether and where candidates go on to university, their future earning potential, and even their marriage prospects. Given the stakes, it is easy to see why so many cultures place great importance on exam success. However, is this one-size-fits-all approach to assessment really a good judge of ability and understanding? Or do exam results only tell us about a candidate’s ability to memorise material and perform under stressful exam conditions? Caroline Bayley meets the educators and experts defending traditional exams and those coming up with alternative models of assessment. Tony Wagner from the Harvard Innovation Lab in the US thinks traditional exams will become obsolete in the future as work places change their hiring criteria. Mike Thomas, Vice Chancellor of the University of Central Lancashire in the UK explains why exams can have a negative impact on mental health. Dr Chun-yen Chang from National Taiwan Normal University has conducted research into whether there might be a gene that determines how well we think under exam conditions. Producers Lizzy McNeill and Viv Jones (Image: Students take exams for University, Credit: bibiphoto/Shutterstock)

We all experience negative emotions and find different ways to cope – maybe by exercising or by listening to music. But some people deliberately inflict pain on themselves as a way of managing how they feel. Why? Experts believe 15% of adolescents self-injure at least once, with some children as young as 9 using self-injury as a coping mechanism, albeit an unhealthy one. The behaviour can lead to feelings of guilt and distress; family and friends often don’t know how to help. Catherine Carr explores the impact self-harming has on those who do it and those close to them. She speaks to Matthew Nock, Professor of Psychology at Harvard University who explains the type of person most at risk of engaging in self-injury and the reasons why they use it to regulate their emotions. News reporter, Aidan Radnedge, describes why he began self-harming at university; and how his family and friends have given unstinting support throughout his road to recovery. Writer and editor, Janelle Harris, explains what it was like to discover that her daughter, Skylar, was self-harming aged 11. Now 18 and having graduated from high school, Skylar is no longer injuring herself and is looking forward to going to college next year. Dr Hayley van Zwanenberg, child and adolescent psychiatrist at the Priory Group of mental health hospitals and clinics in the UK, offers advice for parents on how to react if their children are self-harming – and offers alternative coping strategies for those struggling to deal with their feelings. If you’ve been affected by the issues in this programme, please visit the following websites for support and advice: Befrienders Worldwide: http://www.befrienders.org/about-self-harm Samaritans: http://www.samaritans.org/how-we-can-help-you/what-speak-us-about/signs-you-may-be-struggling-cope/helping-you-through-self LifeSIGNS: http://www.lifesigns.org.uk/ Talk Life: https://talklife.co/ Presenter: Catherine Carr Producer: Sally Abrahams (Image: Sad beautiful girl, Credit: Wayhome studio/Shutterstock)

We all do it – sometimes. It can be embarrassing or just the way we organise our thoughts, a tool for remembering what is important. Sarah Outen, who spent four and a half years rowing, cycling and kayaking around the planet, says talking to herself, out loud, may have saved her life on more than one occasion. The actor, Steve Delaney, has created an alternate persona, Count Arthur Strong, whose most vivid character trait is talking to himself. We all have more wisdom than we dare to think we’ve got, according the psychotherapist Philippa Perry, it’s just a matter of speaking it. In this edition of the Why Factor, Matthew Sweet asks who are we talking to when we talk to ourselves. (Photo: A man talks to himself in the mirror. Credit to Getty Images)

Why take on a role where lots of people hate you for doing it? Dotun Adebayo talks to people whose daily life can include verbal and even physical abuse. They include an 18 year old referee in Manchester who has been head-butted and spat upon. He hears about electricity workers in Lagos in Nigeria who are regularly beaten up as they disconnect disgruntled customers. And the plus side of doing a thankless job from a debt collector in Jamaica and death row lawyers in Trinidad and Tobago and Guyana. (Photo: Man at top of pole fixing electric cables. Credit: Umar Shehu Elleman, BBC journalist)

Some people are numbers people – and some are not. One meltdown moment in the classroom is often all it takes to put people off maths for life. But, when you lose the ability to interrogate numbers, it makes it easier to be fooled by fancy figures. In this edition of The Why Factor, Timandra Harkness asks why people are intimidated by numbers. (Image: Frightened looking man surrounded by numbers. Credit: Wavebreakmedia/Shutterstock)

Why would anyone be a goth? What is the appeal of this dark and spooky subculture that embraces death, pain and sadness? Goths have been attacked, abused and are often misunderstood, but still choose to stand out – dramatically - from the crowd. Catherine Carr talks to goths about their music, their dress and their love of the darker side of life. Why has this scene that began in the UK in the late 1970s and has spread worldwide, adapted and endured? She hears from gothic vlogger, Black Friday, about how others react to her striking style and that of her goth husband, Matthius; she learns from Dr Catherine Spooner of Lancaster University about the role and influence of gothic literature in the goth scene and finds out from Professor Isabella Van Elferen of Kingston University, London about the transcendental power of goth music. Catherine talks to gothic blogger, La Carmina, about the extraordinary and extreme goth scene in Japan that includes body modifications; Dr Paul Hodkinson of Surrey University explains the enduring appeal of the subculture and why once a goth, you’re always a goth. And she meets Sylvia Lancaster, whose daughter Sophie, a goth, was murdered because of the way she looked. Presenter: Catherine Carr Producer: Sally Abrahams (Photo: Black Friday and husband Matthius. Credit: BBC Copyright)

How do you start your day? It’s a more complicated question than you think – and that’s because you don’t think about it very much. Quite a lot of what we do, we do every day. We create order by forming habits. From the way we brush our teeth to how we drive a car, ride a bike, or even tie our shoelaces – these are things we do every day without thinking. And it is a good thing we do because if we had to make multiple choices for every single simple activity our brains would just clog up. But there are good habits and bad habits. Ones that help us through the day and ones we cannot control. Shiulie Ghosh explains the difference between these behaviours and why, one way or another, we are all creatures of habit. (Photo: New Habits v Old Habits Credit: Shutterstock)

Why do some short people lie about their height? How much difference does a few inches make? Felicity Evans is 5 foot (152 cm) tall. That’s 5 inches shorter than the average woman in the UK. In this edition, she examines whether society discriminates against short people and if so, why? She asks what’s it like being shorter than normal and how it affects your self-confidence, career choice and overall happiness. She talks to Joe Mangano, who at 5’4” hasn’t grown since he was 15 years old. He describes how it feels to be treated like a child. Orthopaedic surgeon, Dr Dror Paley, explains how he makes patients taller by breaking then lengthening their legs. Felicity meets Vince Graff (5 foot 2”) who shares his experience of finding love and happiness, despite being well below average height; and Isobella Jade, known as the ‘shortest working model in New York City’, offers her advice on how to be successful despite being at least 6 inches shorter than the average catwalk model. The programme also hears from Tim Frayling, Professor of Human Genetics at Exeter University and Lance Workman, Professor of Psychology at the University of South Wales. Presenter: Felicity Evans Producer: Sally Abrahams (Photo: Graphic illustration of the height measurement of a tall and short person. Photo credit: Shutterstock)

The average English-speaker knows about 25,000 words. And yet those 25,000 words can be combined into an infinite number of sentences -not a simple process. Many people believe that, whatever language you speak, the words you know have a profound influence on the way you think. This is a controversial theory among linguists. In this edition of the Why Factor, Lane Greene explains how paying attention to the language we use can give us a greater understanding of our politics, our debates, our cultures and even our own minds. (Image: Top of woman's head with the word "hello" written in different languages floating above. Credit: Aysezgicmeli/Shutterstock)

What lures people to delve beneath the earth, peering into the dark recesses that exist underground? Simon Cox hears from the urban explorers trying to find the hidden layers of cities that exist deep beneath our feet and the danger how do we cope with it and the fear of being in the darkness in an enclosed space. And as we travel, work and explore in deeper, longer more extensive subterranean networks, he asks what’s stopping us from spending more time there by living underground too? Simon speaks to former miner Andy Smith, urban explorer Steve Duncan, caving expert Jules Barratt, engineer and psychologist Gunnar Jonsson and urban planners Professor Anne-Marie Broudehoux and Professor Clara Irazábal. (Photo: Beautiful stalactites in a cave with two speleologist explorers / Photo credit: Shutterstock)

Why do we clap? Becky Milligan uncovers how the highly contagious nature of applause has been exploited by everyone from Roman emperors to today's politicians . She explores the different styles and rhythms. And how it can make us feel on top of the world or make us want to crawl under a stone. With Historian Greg Aldrete, theatre critic Anne Treneman, music academic Dr Marcus Pearce, Mathematician Richard Mann, comedian Mark Cooper-Jones and former Women's Institute Chairman Helen Carey. (Photo: A pair of hands clapping on black background. Credit:BravissimoS/Shutterstock)

Why do men crave these six bumps on their stomach? Why are they willing to risk their lives for this look? We take a journey to ancient Greece to discover the origins of the chiselled abdominals, learn from online stars on how hard it is to achieve one, hear from a man who bought one from a surgeon and how Instagram and the recession are playing a part in the ‘Six Pack’ story. (Photo: Close up of a man's six pack. Credit: LDN Muscle/BBC)

Yoga is an ancient practice that includes meditation, exercise and spirituality. It’s said to date back thousands of years and originate in the east. But why do millions of us do it every day and how has it become so popular over time? There is controversy about different types of yoga and whether they ring true to the original purpose of the practice. So when we do yoga, are we doing it for the right reasons? Valley Fontaine hears from the director of a 98-year-old yoga institute in India, a religious studies professor in the US, an instructor who teaches yoga for you and your dog, founders of a yoga festival in the UK, and the 2016 women’s yoga champion. (Image: Woman in Yoga pose near Indian temple. Credit: Pikoso.kz/Shutterstock)

There is something satisfying about working with our hands. Whether it is making something, fixing something or caring for someone, tactile skills are rewarding and valuable. Maria Margaronis asks what it is about working with our hands that make us so fundamentally human. (Photo: Artist Hitomi Hosono holds her ceramic pot)

Why is listening different from hearing? What is the skill of listening and how can we develop that skill? (Photo: Close up of woman's ear. Credit: Photomediagroup/Shutterstock)

For most of us, speaking fluently comes naturally. But if you have a stutter, getting the words out can be a real struggle. Some sounds are repeated or prolonged or a word gets stuck and doesn’t come out at all. At times it’s impossible even to say your own name or where you live, which can cause huge distress and embarrassment. Stammering or stuttering (it’s the same thing) affects more than 70 million people globally – that’s about 1% of the world’s population. It’s a neurological condition, based on the brain’s wiring. But other factors, like genetics, also play a part. Becky Milligan examines why some people develop a stammer, what treatments are available and whether stammering can ever be cured. Becky talks to Dr Deryk Beal from Holland Bloorview Kids Rehabilitation Hospital, to find out how the brain of someone who stutters is different from someone with no stutter; she visits the Michael Palin Centre for Stammering Children where 12 year-old Sam is getting treatment from speech therapist Kevin Fower; we hear from 22 year-old Rishabh Panchamia, who was so ashamed of his stammer he considered suicide. He’s now found fluency with the help of the McGuire programme. And Becky meets Betony Kelly who tells us that being open about having a stammer has helped her to accept and be proud of it as part of her identity. (Photo: Rishabh Panchamia playing snooker. Credit: BBC Copyright - Rishabh Panchamia)

It’s probably something we take for granted and do every day - whether a toothy grin, a megawatt beam or just a slight upturn of the corners of the mouth. But have you ever considered why we smile and what effect is has on other people? Scientists say it’s one of our most basic human expressions and it’s easier to smile than to frown. Aasmah Mir explores the power of the smile, how easy it is to fake and what happens when you lose the ability to smile. Aasmah discusses the science behind a smile with Marianne LaFrance, professor of psychology at Yale university and with neuropsychologist, Dr Hamira Riaz. She talks to Jonathan Kalb, professor of theatre at Hunter College, City University of New York, who lost his smile overnight, and speaks to 16-year-old Teegan O’Reilly from Dublin, Ireland, who was born with a rare neurological condition which means she can never smile. Aasmah also hears from Dr Subodh Kumar Singh, director of GS Memorial Plastic Surgery Hospital in Varanasi, who has created thousands of smiles at his hospital in India. And meets photographer Rick Pushinsky, who reveals what happened when the wife of a former British prime minister smiled too much. (Photo: Smiling mouth. Credit: Thinkstock)

Hypochondria: the fear of having a serious, undiagnosed illness. We may mock the hypochondriac, but a constant fear of sickness and death can be a debilitating and distressing condition in itself, with some sufferers even ending up in wheelchairs. So why don’t we take this misunderstood malaise more seriously? Presenter: Becky Milligan Producer: Ben Crighton (Photo: Man in white coat with placing stethoscope on man's chest. Credit: Michal Kowalski/Shutterstock)

In his first TV interview as US President, Donald Trump claimed that torture “absolutely” works and said the US should “fight fire with fire.” But what evidence is there that torture is an effective method of obtaining valuable intelligence? And can the use of torture ever be justified? Becky Milligan hears from a former interrogator who worked at the Abu Ghraib prison in Iraq and now calls himself a torturer, a former political prisoner who was tortured in the notorious Evin prison in Tehran, and a neuroscientist who has studied the effects of torture on the brain. (Photo:Man sitting in chair with hands tied together behind his back with a bucket on the floor. Credit: Rommel Canlas/Shutterstock)

Can deep-frozen bodies ever return from the dead? Before death you can express a choice about what happens afterwards. Burial perhaps? Cremation? Or something else? Maybe you could ask for your body to be pumped full of anti-freeze, then suspended, upside down, in a vat of liquid nitrogen at 196 degrees below zero, in the hope that the medicine of the future can resurrect you. Is this wishful thinking or the secret to a very, very long life? Mike Williams explores the science, the motivation and the ethics behind cryonics and asks whether frozen human bodies will ever be fit for a new life. Contributors: Peggy Jackson, hospice social worker Robin Hanson, associate professor of economics, George Mason University, USA Danila Medvedev, co-founder and deputy director, KrioRus Barry Fuller, professor of surgical sciences and low temperature medicine, University College London Medical School Clive Coen, professor of neuroscience, King's College, London Nils Hoppe, professor of ethics and law in the life sciences, University of Hannover, Germany Presenter: Mike Williams Producer: Sally Abrahams (Photo: Peggy Jackson and Robin Hanson. Credit: BBC Copyright - contributors gave us permission to use this image)

Regret – why do we feel this negative emotion? Is it right to live with it, or should we simply get over our mistakes of the past? Mike Williams speaks to a palliative care nurse who recorded the regrets of the dying, and the man with 50,000 regrets, all entrusted to him by anonymous strangers who have confessed the biggest regrets of their lives on his website. (Photo: Statue of woman with head in hand. Credit: Cheryl E. Davis/Shutterstock)

In 1994, most Americans said they owned their gun for sport or hunting. Fast forward twenty years and now most people say they have their gun for self protection. So what changed in this time; did crime increase? Actually, the data shows that crime has declined significantly over time. So what are people really scared of? And is it rational to respond in this way? We visit a gun licensing class in Texas, USA to hear what prompted people to sign up. We also hear from Angela Stroud, sociologist and author of the book Good Guys With Guns, who argues that it’s not crime people are scared of, but something much less tangible. We also hear from a psychologist in a country you may not associate with guns….neutral Switzerland. They have the third highest gun ownership rate in the world, after the USA and Yemen. So why do so many people have guns there? Is it really just as simple as protecting ourselves from harm? Presenter: Aasmah Mir Producer: Phoebe Keane (Photo: Maria Mathis practices shooting her handgun on her ranch in Texas, USA. )

What drives some people to take the law into their own hands? Mike Williams hears stories from Europe, Africa and the US. Stories about the men – and it is usually men – who take it upon themselves to patrol the streets or seek out paedophiles online. And, he explores what happens when vigilante groups mutate into monsters. Whether motivated by revenge, frustration or a desire to do good, does mob justice ever work? With contributions from Scott and Callum, co-founders, Dark Justice; Laurie James, forensic criminologist, based in Botswana; Curtis Sliwa, founder of Guardian Angels; Kate Meagher, associate professor, Department of International Development, London School of Economics; Jim Gamble, former chief executive, Child Exploitation and Online Protection Centre; Abubakar Bukar Kagu, solicitor and advocate of the Supreme Court of Nigeria Photo: Close up of Guardian Angels' jacket with other men sitting in background, Credit: Mario Tama/Getty Images

Lists of things to do and things to buy. Presents we want for Christmas, or things we desire in a lover. Lists help us organise our thoughts and bring order to a confusing world. But what do they reveal about us? (Photo: An original Madonna handwriten 1990 'to do' diary. Credit: Henry S. Dziekan III/Getty Images)

Could you forgive the person who killed your child or who raped or tortured you? Some crimes, some events are so awful, so cruel, it’s impossible to imagine ever being able to say to the wrongdoer, ‘I forgive you’. Mike Williams hears the stories of those who have experienced unimaginable pain and suffering at the hands of others. And discovers what it feels like to turn anger and desire for revenge against the perpetrators into compassion and understanding for them. What does the act of forgiveness mean to the offender? The programme explores how learning to forgive can make us happier and healthier. But how in some cases, the atrocity is so enormous that forgiveness is a step too far. Contributors: Madeleine Black, Counsellor based in Glasgow, Scotland Robert Enright, Professor of Educational Psychology, University of Wisconsin, USA Martin Palmer, Theologian and Historian of religion Sarah Heatley, mother of Nina and Jack Kemal Pervanic, survivor, Omarska concentration camp during the Bosnian war Presenter: Mike Williams Producer: Sally Abrahams (Photo: Family standing on cliff edge with hills in background. Credit: BBC Copyright (with permission from contributor)

Everyday millions of us across the world get into our cars and drive. For many of us this will be an unpleasant experience because of the behavior of other drivers or even because of our own bad behavior. Even the calmest person can become a raging demon while driving, screaming and swearing at the other road users. What is it about driving that makes some people so angry? What can we do to stop it? We speak with professional racing driver Nathalie McGloin about keeping control. Dr Mark Sullman tells us what happens in our heads when we get into the driver seat. Comedian Rhod Gilbert gives us a passionate description of what gives him road rage. Monica Chadha describes driving in Delhi. And, Glenn Scherer gives us a lesson in ‘car yoga’ to try and keep the rage away. (Photo: Man shouting at woman sitting in car. Credit: Shutterstock)

The desire for vengeance – to harm those who’ve harmed you - is part of human nature. Whether it’s getting your own back on a cheating partner or settling a score with a childhood bully, many of us have considered retribution against the person who’s done us wrong. Yet often we decide not to act on that instinct. So what motivates someone to take revenge and why did this kind of aggressive behaviour evolve? Mike Williams talks to a perpetrator who found it sweet and hears the tragic story of a victim of impossibly cruel revenge. Contributors: “Annie”, who took revenge Michael McCullough, Professor of Psychology, Miami University Dr David Chester, Assistant Professor of Psychology, Virginia Commonwealth University Sarah Heatley, mother of Nina and Jack Philippe Sands QC, International Human Rights lawyer and author, East West Street Professor Jack Levin, Co-Director, Brudnick Center on Violence and Conflict, Northeastern University, Boston, Massachusetts Presenter: Mike Williams Producer: Sally Abrahams (Photo: White Voodoo doll with red pins on cork background. Credit: Shutterstock/Scott Rothstein)

Why don’t we understand how the female orgasm works? After years of scientific research, the male body is understood but when it comes to how women work, we are a long way behind. Why is there this gap in knowledge? It appears research has been hindered by the assumption that the female body works in the same way as the male body and that for women, arousal is all in the mind. There’s also a general attitude that studying sexual pleasure isn’t important and that female orgasms aren’t important to study as they serve no purpose for reproduction. Researchers are slowly correcting these assumptions and making surprising discoveries. We’ll take you behind the scenes to two orgasm labs to bring you the latest research on how orgasms work for women. We’ll also hear from Callista, who struggled with excruciating pain during sex for many years but was told the problem was all in her mind. Her journey to diagnosis shows how little is known, even amongst gynaecologists and doctors, about female sexual pleasure. Presenter: Aasmah Mir Producer: Phoebe Keane (Image: Woman's hand grasping a bed sheet. Credit: Shutterstock)

When we are surrounded by people why do we tend to shun them? Why do we refuse to make eye contact or say hello? And, why do tempers flare on busy city streets? More and more of the world’s population are moving to cities. As they swell in size our behaviour changes and not always for the better. It is a familiar scene, a busy metro carriage with people pushing and shoving but never saying hello or even making eye contact. Why do cities make us act this way? To find out we speak to social psychologist Dr Elle Boag about what is happening inside our heads. We ask Marten Sims of the organisation Happy City Lab if buildings can make us rude. We perform the Lost Tourist test to find out just how rude London is. Olivier Giraud tells us why Parisians never give up their seat to pregnant women on the metro. And, Manhattan manners expert, Thomas Farley defends the city and explains the reason we often have to act the way we do. (Photo: Man and woman arguing on street. Credit: Shutterstock)

Mike Williams asks why so many people are obsessed with discovering their family origins and also learns new things about his own ancestors along the way. Genealogy is a growing phenomenon driven by the digitisation of old paper records, websites offering to DNA test your saliva for $100 and TV shows like Who Do You Think You Are, which explore celebrities family histories. But what does spending hours, weeks and – in some cases – years trying to discover names or dates that might reveal the identity of someone related to us hundreds of years ago say about us? And, what are we really looking for? Mike talks to Else Churchill at the Society of Genealogists in London, Nathan Lents, professor of molecular biology at John Jay College in New York and Catherine Nash, professor of Human Geography at Queen Mary University of London. (Photo: Paper cut of family symbol under tree on old book. Credit: jannoon028/Shutterstock)

Imagine your home is so filled with stuff that moving around it is almost impossible. Every bit of space is piled high with books, pictures, DVDs and newspapers so you can’t even get into some rooms – not even the bathroom or kitchen. There’s nowhere to sit and no room for visitors. That’s what life is like for those with a hoarding disorder and their close family and friends. It’s a recognised mental illness, an uncontrollable desire to acquire and keep an excessive number of objects and it’s thought to affect between 2-6% of the UK and US population. So why do some people hoard? And why is it so difficult for them to get rid of some of the many thousands of items that clutter their home? Mike Williams meets Stephen whose apartment is so swamped with possessions that his young children can’t stay. He hears how the extreme hoarding habits of one American father led his teenage daughter to make a suicide bid. And, on a positive note, there are lessons for compulsive hoarders on how to resist the urge to acquire more things. Contributors: Bill Barry and Stephen, Tenants, Liverpool Housing Trust Randy Frost, Professor of Psychology at Smith College, Northampton, Massachusetts Heather Mattuozzo, Founder, Clouds End Fabio Gygi, Anthropology lecturer at the School of Oriental and African Studies, London University Kimberly Rae Miller, author, ‘Coming Clean’, a memoir Presenter: Mike Williams Producer: Sally Abrahams (Photo: Lots of clutter in a front room. Credit: BBC Copyright - taken in contributor's house by presenter with contributor's permission)

Are you sexist, racist or ageist? Even if you think you are open-minded, the chances are, you will be judging people and situations without even realising. These hidden biases – which are different from conscious prejudice – lurk within our minds. Science clearly shows that almost all of us have at least one of these tendencies - an implicit preference for one race over another, for men over women, for young over old or vice versa. Our unconscious biases are influenced by our background, our personal experiences and the culture in which we live. And, they can affect the way we behave, the decisions we make - whether it is who we hire, who we promote or even – in the case of jurors – who we believe is guilty or not guilty. Mike Williams learns about an online assessment test that measures unconscious bias, explores the extent to which we can we limit these hidden biases, once we are aware of them. And, hears how one orchestra, in particular, has a solution to the problem – by asking prospective players to remove their shoes. Contributors: Mahzarin Banaji, Professor of Psychology, Havard University; Dr Pete Jones, Psychologist; Nick Logie, Orchestra of the Age of Enlightenment; Yassmin Abdel-Magied, mechanical engineer and founder, Mumtaza speakers bureau; Kayo Anosike, Music Director/Kayla Benjamin, Training Consultant; Margenett Moore-Roberts, Yahoo’s Global Head, Inclusive Diversity; Patrick Brayer, criminal defence attorney, St Louis, Missouri. (Photo: Man holding a baby whilst ironing and woman fixing car. Credit: Volkovslava & Wavebreakmedia/Shutterstock)

Can you believe your own eyes? Can you trust your own memory? Why is it that so many social scientists and so many in the police and the judiciary are so very concerned about eye-witness testimony. Mike Williams talks to an attorney at the Innocence Project in New York, a retired judge, a professor of psychology and a memory expert in an attempt to find out why we try – and often fail – to accurately recall a face or an event. (Photo: Black and White image of four men in a suspect line up. Credit: Shutterstock)

It has become quite a common thing but when you think of it, it is remarkable that we can take a part of one human (dead or alive) and insert it into another to cure them. Last year across the planet, an estimated 119,000 people received transplants but many more are still waiting. In the United States alone more than 120,000 are on the waiting list for an organ transplant. For many people, that life-saving operation will have to wait until someone else dies. Mike Williams talks to a surgeon in the United States, a doctor in Israel whose direct action led to an improvement in donation rates, a daughter who gave a kidney to her father and a man who altruistically donated a kidney 20 years after a family tragedy. (Photo: Man and daughter smilling. Credit: Nicholas Evans)

Why do we write farewell letters? Whether it is messages from the living to the dying or from the dead to the living, how can we find the words to say goodbye? A letter from a daughter to her dying father, a last letter from a soldier on the eve of battle, messages of love from a dying mother to her young daughter and a suicide note from a father to his teenage son. Mike Williams explores the comfort and pain of goodbye letters. Contributors: Susan Geer, Last Goodbye Letters; Joe Williams, The Enemy Within; Brendan McDonnell, Herman’s Hands; Laura Colclough; Julie Stokes, Founder, Winston’s Wish; Anthony Richards, Imperial War Museum. (Photo: Woman and child walking along woodland path. Credit: Shutterstock) (Clip credit: The Mummy Diaries (2007), Ricochet/Channel 4 TV)

Why do we feel so many different and intense emotions when someone close to us dies? Whether it is yearning, sadness, anger or even shame, Mike Williams explores why each person’s grief is unique. The pain of losing a loved one initially seems so unbearable, yet most bereaved people do eventually find a way to adjust to their changed life. So what happens when we grieve and why does grief sometimes get complicated? Mike talks to Bill Burnett, who is learning to live without his wife, Betty. She died in 2010 after 43 years’ marriage, yet Bill still talks to her photo and asks her advice. And, we hear from Rhonda O’Neill who lost her husband in a plane crash and then her young son to kidney disease two years later. She describes feeling tormented by the belief she could have done something more to save her son’s life. We also hear from eminent UK psychiatrist Dr Colin Murray Parkes, who describes what happened to one of his patients who buried his grief, and from Dr Katherine Shear, professor of Psychiatry at Columbia University and director of the Center for Complicated Grief. (Photo: A woman hugging a man. Credit: Vibe Images/Shutterstock)

Is it ever right to take a life? Mike Williams explores the ethical dilemmas of assisting death. In a few countries, terminally-ill people — suffering pain and distress — are allowed to get help from friends, family and physicians to bring their lives to an end. In many countries, it’s a crime. Helping someone to kill themselves is illegal in the UK but there are attempts to get the law revised. The rules are most liberal in Belgium where, recently, a 17 year old boy became the first minor to be granted help with dying. And, in the United States, California has become the fifth state to approve what they’ve called “physician assisted death”. Presenter: Mike Williams Producer: Ben Carter & Kara Digby (IMAGE: Woman touching elderly man's hand. Credit: Arman Zhenikeyev/Shutterstock)

Pokemon Go has been the runaway success of the summer but why is it that some games, hobbies and activities become crazes while others do not? Is there a secret formula? Johanna Basford, the illustrator behind the current adult colouring book craze and Cheong Choon Ng, who invented the Rainbow Loom, explain how they managed to get their ideas off the ground and loved by millions. We hear from psychologist Ben Michaelis that insecure people are more likely to engage with crazes than people who have a lot of self-confidence. Matthew Alt, co-founder of Alt Japan, a company which produces English versions of Japanese games, explains why so many childhood crazes of the last 30 years including Transformers, Power Rangers, Tamagotchi and Pokemon started in Japan. Presenter Aasmah Mir also takes a trip down memory lane, trying out hula-hooping at a class in London after enthusiastically abandoning the fad 30 years earlier. Is she any better now? Hula-Hoop teacher and performer Anna Byrne explains why the craze is making a comeback. But not all fads are harmless fun. Sometimes playground crazes can go wrong and have devastating consequences. Sabrina Lippell talks openly about the tragic death of her twelve-year-old son William Stanesby after he took part in the so-called ‘choking game’ that encourages participants to restrict their airways. (Photo: A hand holds a phone showing a Pokémon character on screen. Credit:JoeyPhoto/Shutterstock)

Why are we so fascinated with the likes of Batman, Superman and Wonder Woman - the superheroes which populate our cinema screens and comic-books? These modern, mythical, magical titans emerged from 20th century comic books but they’re descended from ancient heroes… Hercules and Odysseus, the Nordic Thor, the Babylonian Gilgamesh. Today they help keep film companies afloat by inspiring billion dollar blockbusters. Mike talks to Jim Higgins is a writer and editor of comics, Nina Nazionale from the New York Historical Society, Steven Walsh, a bookseller at Gosh Comics, Jason Ditmer, a professor of political geography at University College London and Dr Casey Brienza, a sociologist at City University in London. (IMAGE - Superman, Robin and Batman standing in a booth. Credit - Hulton Archive / Handout, Getty Images)

On the last episode of The Why Factor Mike Williams explored the human voice in all of its unique power and beauty; this week we investigate its unique ability to irritate and annoy. We all have our personal bugbears when it comes to irritating voices: nasal, monotone, high-pitched or certain types of accent; but why do certain types of voice wind us up so much? And does that irritation reveal more about the speaker or about ourselves? Neuro-biologist Professor Sophie Scott and linguists Rob Drummond and Rob Pensalfini help us to decipher whether there is anything intrinsically annoying about certain sounds or whether it is all about social conditioning: our own biases and prejudices. Are irritating voices the same the world over? Why does the Australian accent get picked on? And what is vocal fry? Finally, what if it is your voice that everyone hates? Mike talks to Laura Ashby, a contestant on the US game show Jeopardy! Whose voice led to a social media meltdown and to her receiving death threats. Presenter: Mike Williams Producer: Rose de Larrabeiti (IMAGE: B/W image of boy with fingers in his ears and girl leaning on his shoulder. Credit: Dennis Oulds/Getty Images) Credits for clips used: American Pie (1999) Universal Pictures. Director: Paul Weitz Comedian Adam Hills, Melbourne International Comedy Festival Gala 2006 Jeopardy! Sony Pictures Entertainment Inc. Fresh Air presented by Terry Gross from WHYY/NPR This American Life presented by Ira Glass from WBEZ/NPR The Vocal Fry Guys courtesy of Ann Heppermann UP (2009) Walt Disney Pictures and Pixar Animation Studios. Director: Pete Docter

We each have a unique voice, shaped by our biology, history, class and education. It is a powerful tool and we are often judged by the very first words out of our mouths. Mike Williams discovers what makes one voice trustworthy and another not. We hear from a voice coach about how we can adapt and deceive with our voices and a vocalist demonstrates the power of the voice as an instrument. We also hear from an American teenager who has been voiceless since birth but whose personalised computerised voice has enabled her to find her own. Audio clip of Elaine Mitchener, taken from Focus (2012) by Sam Belinfante, courtesy of The Wellcome Collection. (Photo: Woman singing into microphone. Credit: Shutterstock)

Introverts. People who are often labelled as shy, a term coined following the work on personality types by German psychologist, Carl Jung, in 1921. But introversion is much misunderstood. Introverts recharge their batteries by being alone whereas extroverts are the opposite and crave crowds. Emerging research on the biochemistry of the brain indicates that the neurotransmitter dopamine – the chemical released that provides motivation to seek rewards, is much more active for extroverts than for introverts. According to Phd and introvert researcher, Lisa Kaenzig, introverts are much less valued today than they used to be. In the past, some of the world’s most renowned thinkers, religious leaders, philosophers and writers were held in the highest esteem – many of them were working alone and were at their most creative in solitary study. However, she is part of a growing movement which is challenging a seeming bias in favour of the extrovert – for the person who talks first in meetings and makes off-the-cuff remarks and who may shout the loudest to get their ideas heard. The growth of the open plan office, group thinking and collaborative learning are all enemies to the introvert, but in recommendations by Dr Peter Aloka – a Kenyan psychologist who has been studying introvert teenage mothers in Bondo, the answers lie in teaming introverts up with extroverts and calling upon introverts to present group findings and allowing extra think time in response to questions. Where do you lie on the introvert/extrovert scale or are you in the middle – an ambivert? If you are an introvert, you’re in very good company; Barack Obama, Rosa Parks, JK Rowling and many more eminent and thoughtful people are introverts. Presented by Anu Anand Produced by Priscilla Ng’ethe and Nina Robinson (IMAGE: Words in white chalk describing personality types on a blackboard. Credit - marekuliasz, c/o Shutterstock)

The Why Factor is about our pets on the internet. Those viral videos of our cats stalking us or the dogs saying I love you. Why have cats become celebrities and why do we love to watch and follow them on social media? Mike Williams meets the cat at the top of the viral video tree; the one and only Grumpy Cat with twelve million followers, her owners and business managers are just trying to keep up with all her fans. Assistant Professor Jessica Gall Myrick from Indiana University, conducted an online survey of some 7000 cat video watchers and found that people felt happier watching them and were less likely to feel anxious or sad. With all that happiness around, the creator of NyanCat – an animated cat flying through space with a rainbow trail and catchy tune to match, has a mind-boggling 133 million views last time Chris Torres checked. He tells The Why Factor why he thinks it has been such a viral sensation. We also talk to Jason Eppink, curator of a recent exhibition at the Museum of Moving Image in New York on ‘How Cats Took Over The Internet’. Then there is a serious side to all this cat, dog, chicken and goat watching online. Anh Xiao Mina – a writer and researcher has been looking at the growth of ‘cute cat digital activism’ – the theory that pet viral videos are teaching us important lessons about what we can say and do online and could, in the future, be used to promote new social movements. Presented by Mike Williams Produced by Nina Robinson (IMAGE:Grumpy Cat at the BBC, Nina Robinson - BBC Copyright)

Why do we still fear animals that pose no serious threat to us and how can the effect of that irrational fear be so overpowering? As Mike Williams discovers in this week’s Why Factor, the answers lie deep in our evolutionary past and deep inside our brains. Mike faces his own animal fear at London Zoo, where we also meet people overcoming their fear of spiders. Arachnophobia is one of the most common animal phobias and American Psychologist Joshua New’s research suggests humans are better at identifying and locating spiders than any other perceived threat. Could our fear of spiders be a leftover from our evolutionary ancestors? Neuroscientist Dr Dean Burnett reveals what happens in our brains when we’re frightened by animals, and this is not always by the traditional spider or snake. We hear from a woman in Greece who has a rather surprising animal phobia… Presenter: Mike Williams Producer: Rose de Larrabeiti Film clip: 1984 (1984) Umbrella-Rosenblum Films Production. Director: Michael Radford Image: A tarantula spider. Credit : Credit: Miguel Rojo/Getty Images

Mike Williams asks if we now live in a post-factual age — where messages of fear dominate and the truth goes unspoken or unheard? He investigates the “Backfire Effect” which means that entrenched views can become more entrenched – when confronted by contradictory facts. Politicians are often accused of distorting the truth – with Republican Presidential candidate Donald Trump the latest. (Image - Group of people standing with one holding a newspaper with the headline "Earth Doomed". Credit - Everett Collection via Shutterstock)

Why do we love driving? Mike Williams asks if we would miss driving, as auto-piloted cars are tested in cities around the world. He talks to Dr Lisa Dorn, psychologist and associate professor of driver behaviour, Dr Zia Wadud an associate professor in transport studies, technology reporter Brian Fung, racing team owner Eddie Jordan and top gear presenter Sabine Schmitz. (Photo: White driverless car on road. Credit:Noah Berger/AFP/Getty Images)

Anybody who watched the European Championships of football this summer in France would have seen shocking scenes of violence between fans. The vast majority, if not all, were men. Men also commit more than 90% of murders across the world and are more likely to join a gang. Why are men more violent than women? Caroline Bayley speaks to ex-football hooligan Cass Pennant about his experiences and motivation when violence became his way of life. Former British Army officer Jane Middleton explains the differences between men and women on the battlefield when she served in Afghanistan. And, Caroline also hears views from Sweden about how equal violence between men and women in relationships is. (Photo: Group of football fans fighting in street. Credit: Carl Court/Getty Images)

For many decades now we’ve been getting smarter. All across the planet average IQ results have been rising… by about 3 points every ten years. It’s called the Flynn Effect and it’s changing our societies. So what is it? What causes it? And what could be the consequences if — as seems possible — it goes into reverse. (Image : Woman and man standing back to back with think bubbles. Copyright - Racorn/Shutterstock)

Free, digital news is threatening traditional newspapers around the world, so why do they survive and what is their future? Mike Williams speaks to legendary newspaper editor Sir Harry Evans and journalist in exile Qaabata Boru who fought to set up an independent newspaper in a Kenyan refugee camp. Mike also hears from Melody Martinsen who owns and edits The Choteau Acantha, a tiny newspaper in rural Montana where not even the premature birth of her son stopped publication. And at the British Library’s newspaper archive, Mike learns how, as chronicles of ordinary people’s lives, newspapers can throw up some surprise stories missed by the history books. (Image: Early edition of the Daily Mirror spread on table. Credit: Image courtesy of the British Library)

Why are we attracted to some people and to not others? Mike Williams explores the factors that lie behind our feelings of attraction. He speaks to the authors Christy and Clare Campbell. Christy fell in love at first sight, but it took Clare six months to feel that strong sense of attraction. After 40 years of marriage they are still attracted to each other. Beauty, facial symmetry, personality and values all play a role in our attraction to others. Evolution biologist Dr Anna Machin from Oxford University explains the science behind attraction. Dr Machin explains how chemicals released in our brains gives us the confidence to approach someone who we are attracted to and how the smell and taste of a prospective partner can tell us a lot of their genes and whether they will be a compatible mate. (Photo: A couple gazing at each other. Credit: Shutterstock)

What is loneliness and why do we feel it? Why do some people feel lonely when surrounded by people and others never feel lonely at all. Mike Williams finds out why feeling lonely can help us to survive. Feelings of loneliness do not only come from the position we can sometimes find ourselves in. Studies of twins in Holland have shown that loneliness has a hereditary element. And surprisingly loneliness can also be contagious. Mike speaks to the Chinese artist Li Tianbing about how growing up under China’s one child policy shaped his art and to a Swedish entrepreneur who invited 11 people to come and live with her to combat her loneliness. (Photo: Woman alone on a bridge. Credit: Shutterstock)

The ideal university experience is expected to train the minds of students by exposing them to new ideas and challenging their assumptions. Why then, in the English speaking west at least, are some students rebelling against this principle by insisting there are some ideas which are so abhorrent they should not be heard? To them a university should be a safe space. In this edition of the Why Factor, Mike Williams tries to discover where the balance lies between freedom of speech and protection from offence and asks what exactly is a safe space? Producer: Sandra Kanthal Image: Students sharing space on campus (Credit: Rawpixel/ Shutterstock)

Why do people try to create old masters and modern art, brush stroke by brush stroke? And, why do people buy them? He talks to art copier David Henty, fine art expert and gallery owner Philip Mould, Paul Dong a Beijing based art auctioneer, Colette Loll founder and director of the Washington-based Art Fraud Insights and art copy customer Patricia Burns from Canada. (Photo: A copy of Pablo Picasso's The Weeping Woman painted by David Henty, courtesy of the artist D.Henty)

For thousands of years, a thin body was a sign of poverty or disease. But there is now a growing, global obsession with being thin. And this at a time when many populations around the world are, paradoxically, suffering epidemics of obesity. Mike Williams finds out why, as he speaks to former French model Victoire Macon Dauxerre, Tony Glenville from the London College of Fashion, Anne Becker from Harvard Medical School, Professor John Speakman from University of Aberdeen and Etta Edim from Nigeria’s Efik tribe. Image: A vendor arranges stick-thin mannequins in a store in China (Credit: China Photos/Getty Images)

Robots are in our homes, our factories, on battlefields and in hospitals. Some are smarter than us, some are faster. Some are here to help us, others not. Science fiction is filled with malign machines which rise against humanity. In the Why Factor this week, Mike Williams asks if we have reason to fear the machines we are creating. Insert: “I, Robot” 2004 Twentieth Century Fox. Director Alex Proyas, based on story by Isaac Asimov Insert: "Astro Boy"- Ep.1: The Birth Of Astro Boy (in English) © Nippon Television 1982 (Photo: Robots in Suits © Shutterstock)

Mike Williams asks why some weeks just fly by but sometimes minutes can seem like hours? Why do we perceive time differently in different circumstances? Mike talks to Pakistani writer and broadcaster Raza Rumi; Claudia Hammond, author of Time Warped; David Eagleman, a neuroscientist at the Baylor College of Medicine at Houston and John McCarthy, a British journalist taken hostage in Lebanon in 1986. (Photo: Hands of a clock over female silhouette. Credit: Shutterstock)

For thousands of years mankind has erected pillars of public art. Statues exist across almost every culture. To some they pay homage to gods, to others they are attempts at immortalising man. Their toppling has become a symbol of regime change. They are worshipped and prayed to, idolised and in some cases despised. They are a unique art form that has seemingly never gone out of vogue. Lucy Ash explores the significance of these sculptures and speaks to Jasleen Kaur, a young artist whose art examines if history can be retold through art. In the UK, the Oxford University campaign to remove a statue of the controversial figure, Cecil Rhodes, has sparked a passionate debate around the way we view the past. In South Korea, she speaks to protest sculptors whose statue of a little girl outside of the Japanese embassy in Seoul almost derailed a 10-year Korean-Japanese relations agreement. Lucy examines why societies insist on placing its people on pedestals. What are the motivations behind the commissioning of statues? And, what sentiment can they project onto a population? Why have the building of statues become pet projects for the politically powerful? And, can culture be exported across borders and can any statue really stand the test of time? (Photo: Kim Seo-kyung (left) and Kim Eun-sung (right) sculptors of the 'Comfort Women' statue)

As part of the BBC World Service “Identity” season The Why Factor explores how the one of the fundamental tenets of our personal make up, our national identity. Few countries have a stronger sense of themselves than the United States of America and few are so strongly drawn in the minds of people right across the world. The ubiquity of McDonalds, America’s unflinching patriotism and loyalty to the flag, the country’s foreign military interventions, sometimes disastrous, other times not, its religious devotion and its long drawn out, highly public elections, all form part of the uniquely American character. In this documentary, Mike Williams asks what makes up the identity of an American. At Ellis Island in New York, he will explore the setting which greeted generations of European immigrants who made the country a melting pot. He will visit the Alamo in Texas and the Smithsonian in Washington D.C. to draw on America’s myths and legends and ask how a unique devotion to the Constitution has evolved into a devout and demonstrative patriotism which seems ubiquitous in all walks of life. And, he will look at the ever present issues of race and wealth and ask if they still determine the identity each citizen has placed upon them. (Image: Crowds at the Veterans Day ceremony in Washington DC/ Credit: Win McNamee/Getty) US National Anthem sung by Lady Antebellum at the 2010 Sugar Bowl

Mike Williams asks what the rest of the world thinks of the United States, one of the most recognisable nations on the planet. This is the second part of a programme looking into the concepts of identity for the BBC World Service's Identity season. (Photo: The American Flag. Credit: Spencer Platt/Getty Images)

Pop, Blues, RnB, Hip Hop, Folk, Reggae, Metal - why do we like the music that we like? As part of the Identity Season, BBC Radio 1 presenter Gemma Cairney asks why we listen to the music we do. What is the importance of music in forming an identity in adolescence, be it a social identity, a gender identity or another group identity? In a world where the internet gives us access to what everyone else is listening to – what does what’s on our playlist say about us? Do record companies and media outlets dictate what music we end up listening to, or are they led by audiences’ preferences? Singers, songwriters, radio DJs and music experts explain how the recipe for international success in the music industry has changed over the years. Although the popular music charts and radio playlists can give an indication of what people like to listen to, streaming has become an increasingly popular way to listen to music, and the data behind the streams reveals nuanced listening habits among different cities and age groups. This documentary includes lively interviews with international stars, record industry experts, academics and music writers providing a range of perspectives on our diverse musical tastes. Gemma will speak to music fans in different parts of the world, asking them why they choose the music they do, and how it shapes their identity. The programme is filled with a rich variety of music, both recorded and live performances, from the Lollapalooza festival in Chile to the haunting sounds of Iceland. Produced by Flora Carmichael and Peter Snowdon (Photo: Gemma Cairney in Reykjavik exploring Iceland’s unique musical identity)

What are notions of national identity and how does it arise? We look at probably the most powerful country on the planet - the United States of America. What is its character? And what do Americans see when they look at themselves. Mike Williams travels around the States to uncover the ideology involved in being an American. (Photo: The Statue of Liberty. Credit: Timothy A.Clary/AFP /Getty Images)

When there are so many ways in the world we can listen to music, why does getting your request played on a radio station feel universally so special and exciting? Gemma Cairney speaks to music fans and radio stations from Mexico to Myanmar. They tell us why a request can bring so many people together and sometimes leave even listeners and DJs in tears. And, we find out how radio stations across the world are finding new ways to allow song requests to interact with their audiences and keep them tuning in. (Photo: Country cowboys in Uganda. Photo Credit: Will Boase)

Lee Kumutat examines why blindness comes to define the identity of people who have little or no sight. And why is sight so highly prized by people who have it. She talks to people in Kingston Jamaica, Accra in Ghana, in Edinburgh Scotland and California in the US. She asks how they navigate a world which seems to see them in two ways. People who are blind it seems must either be inspirational or deserving pity. Or even both. (Image: Catherine Gilliland)

As part of the BBC World Service Season on Identity, The Why Factor examines one simple question: Who are you? Did you choose your identity or was it given to you? Mike Williams asks how our identities are created and if that shapes the way we see the world, and the way the world sees us. (Crowds on Oxford Street, London UK. Photo by Dan Kitwood/Getty)

A pregnant Captain Kirk gives birth on the Enterprise, Harry Potter and his rival Draco Malfoy fall in love and you take a starring role in your favourite book, film or TV show. Seems unlikely? With fanfiction any of this - and more - becomes possible. Fanfiction is a global phenomenon with amateur writers creating new stories in the existing fictional worlds of their most loved films, TV shows and books. For many it is an obsession – but why do they do it? And, how do the writers whose works are taken on by the fanfiction community feel about it? It is not for the money; fanfiction is a non-commercial pursuit, although some writers do make the transition from amateur to published author. The most famous example of this is E.L. James, whose blockbuster book 50 Shades of Grey, started out as fanfiction based on the Vampire inspired Twilight series. Chilean author Francisca Solar tells us how her own Harry Potter fanfiction landed her a book contract. But turning pro is not the goal for most ‘fanfic’ writers; it is the freedom to play with their most loved characters in a uniquely creative world, with very few limits. (Photo: A black and white picture of Captain Kirk and Mr Spock credit: Robyn Beck/AFP/Getty Images)

Juju, Evu, Witchcraft, the evil eye, Voodoo, black magic. There are many names for beliefs that supernatural forces can be harnessed by people who are out to cause harm. Harm to someone’s health, finances, relationships, even their political ambitions. Mike Williams asks why these beliefs still appear to have such a strong hold across different societies, crossing boundaries of wealth and education. And why some attempts to combat these “evil forces” might help in reinforcing fear in them. He speaks to Indian rationalist Sanal Edamaruku, anthropologists Dr Hermione Harris and Peter Geschiere, Line Mariani Playfair and campaigner Vicky Ntetema. Produced by Bob Howard (Photo: Human skull on a book next to the clock. Concept of black magic. Credit: Shutterstock)

Tricksters, conjurers, the world of magicians. Who are they and why do they do what they do? We began by asking ourselves why we enjoy magic shows and why we allow them to deceive us. But it turns out that the psychology of the magicians themselves is as interesting as the psychology of the audience. So what is in the mind of a magician? (Photo: A magician performs card tricks with the help of his assistant. Credit: Getty Images)

Throughout history people have held conspiracy theories which cast doubt on the official narratives of some very serious events - from the Holocaust to 9/11, Diana to JFK, Lockerbie to Sandy Hook. What prompts people to think in this way? How should Governments react to the people who doubt them? Or are they in fact critical in our attempts to hold Governments to account? Mike Williams talks to a psychologist, a Professor of Political Science and a conspiracy theorist as he attempts to separate fact from fiction. (Photo: Conspiracy word cloud concept, with abstract background. Credit: Shutterstock)

Mike Williams visits the ultimate cathedral of science, the Large Hadron Collider at CERN, where researchers from around the world have built the largest single machine on earth to discover some of the most extreme elements of nature, from the heart of an atom to the origins of the universe. But what drives the human need to know how the universe began and our desire to keep searching for what our world is really made of – down to the smallest particles on earth? (Photo: A worker walks past a giant photograph of a Large Hadron Collider at an exhibition in Berlin, Germany. Credit to Getty Images)

What happens when the biochemistry of the brain’s pleasure and reward system goes wrong? How can something that starts off being pleasurable end up making us feel so low? Mike Williams talks to scientists and former addicts to search for some answers to the power of addiction. (Photo: Collection of different hard drugs heroin, pills, tobacco and alcohol. Credit: Shutterstock)

Why do we like the things that we like? At the root of it is 3, 4 -Dihydroxyphenethylamine - or Dopamine - a chemical produced by the nerve cells in the brain to signal to others. But as Mike Williams finds out our pleasure circuit can be triggered by some obvious and not so obvious things. (Photo: a young woman listens to music on headphones. Credit to Shutterstock)

Water is the only molecule in the natural world which expands when it freezes. And that is not its only unusual feature. It is the cornerstone of all of life on this planet, and maybe others. Water is part of the myths and rituals of civilisations all over the world. But if H20, the one chemical formula just about everyone can recognise, was just a little bit different, life as we know it would not exist. Mike Williams explains why water is exceptional and what that means for all of us. (Photo: Raindrops on a window. Credit to James Beard)

Impersonators, imposters, con-artists and entertainers – those people who pretend to be who they are not. Some do it for financial gain, some to pay tribute to a music icon and some simply to raise a laugh. But what happens when people start to believe their own stories, start to believe their fantasy life is real? It is mainly men who pose as police officers, soldiers, special forces: figures with a badge, a uniform, some aura of authority. Mike Williams explores what motivates people to be somebody they are not. (Photo: David Boakes impersonating Michael Jackson. Credit to Mike Williams)

The age of consent is the age at which a person is considered by law to be capable of agreeing to sex. It is just a number, but a number which varies greatly around the world. It is bound up with child protection, notions of honour and marriage, and concerns about paedophilia and society’s strange obsession with lust. Mike Williams asks whether the broad range of ages implies the number is simply a social construct or if it is based on any hard and fast scientific evidence. For much of history, laws have regulated relationships between women and men, girls and boys but why does the age of consent for homosexual relationships differ? (Photo: Cartoon graphics of two hands with question marks on a red background, asking yes or no)

On the Why Factor this week, Angie Hobbs asks why do we want or need heroes? What constitutes a heroic act? Is it something you set out to do, or something you don’t choose, but live up to when it’s thrust upon you? And why do societies celebrate heroism? Professor Hobbs talks to people who’ve been hailed as heroes: Colonel Tim Collins who gave a much praised eve-of-battle speech to his troops as they were about to enter Iraq in 2003, Justin Oliphant who tackles gang violence in South Africa and Dame Ellen MacArthur who broke the record for solo round the world sailing. Angie also hears from experts on heroism: psychologist professor Alice Eagly of Northwestern University, historian Sir Max Hastings and MP and explorer Rory Stewart. Produced by Arlene Gregorius and Jessica Treen (Photo of a helicopter rescue. Credit: IStock)

Do as I say, not as I do. No-one likes a hypocrite, and we like being accused of hypocrisy even less. Yet most of us are hypocritical to some degree. So why do we profess one thing but do another? How far is hypocrisy part of the human condition? And what would a world be like without it? Mike Williams presenting. Produced by Ben Crighton (Photo: Hypocrisy Sign. Credit to Shutterstock)

Why do we hunt? In some societies hunting is necessary to get food, but why do those who can buy meat in a shop go out hunting? Do they like to kill? Or is there something else at play? Lucy Ash talks to hunters from Canada, South Africa, the US and Scotland, who between them have killed animals ranging from deer to elephants, to ask them why they do it. She finds out that the majority of hunters don’t actually like the act of killing, but hunt because they enjoy the adrenaline-fuelled tracking, or being out in nature with heightened senses, or simply to provide for their families in a way they find much more satisfying than simply buying meat in a grocery store. And then there are some reasons that go deeper. (Photo: A hunter with this dog and a deer)

Anyone who has ever been in a meeting has seen the phenomenon of "Groupthink" first hand. The will of the crowd over shadows the wisdom of individuals and it can lead to dangerous consequences. Mike Williams asks why humans succumb to "Groupthink" and how we fight the tendency to follow the herd even if it leads to very perilous outcomes. (Photo: A meeting. Credit: Shutterstock)

Lists of things to do and things to buy. Presents we want for Christmas, or things we desire in a lover. Lists help us organise our thoughts and bring order to a confusing world. But what do they reveal about us? (Photo: An original Madonna handwriten 1990 'to do' diary. Credit: Henry S. Dziekan III/Getty Images)

It’s a simple item of dress but one that says much about the societies in which we live. Mike Williams looks at this most basic form of dress the skirt. A rectangle cloth which throughout centuries has been associated with great meaning including women’s liberation and their oppression, politics & gender. The programme includes an interview with Jung Chang, author of the bestselling “Wild Swans”, who describes how the skirt was a dangerous thing to wear during the cultural revolution. Produced by Smita Patel (Photo: Woman wears a polkadot skirt on a green background. Credit: Shutterstock). Credit: Shutterstock)

Mike William looks at the paradox at the heart of the human condition - the desire to belong and to conform, but also to hold onto our individuality. And we see a symbol of this paradox every day in an apparently useless piece of clothing about 150 centimetres long - the necktie. Why do we wear ties? (Photo: US astronaut Buzz Aldrin arrives on the red carpet wearing a colourful tie. Credit: Getty Images)

It’s a style of dress that’s spread around the world - the suit. It’s survived, largely unchanged, for the three centuries. But, where does it come from, what’s its appeal and what does it say about those who wear it? Mike Williams talks to fashion designer Paul Smith who wears one every day and to the author Jung Chang who had no choice but to follow suit during the Cultural Revolution in China. Produced by Smita Patel (Photo: Two men sit side by side wearing sharp suits. Credit Shutterstock)

They’re something you probably see every day… maybe hundreds of them, thousands. Plain ones, coloured ones, funny ones. Often they’re promotional, sometimes provocative. They’re so common that they’re very easy to ignore. From the catwalk to the building site and everywhere in between, these simple garments can be tools of the rebel, the protestor, the campaigner, the corporate marketeer. They are strangely powerful things… but with humble origins. Produced by Bob Howard (Photo: Man wearing a T-Shirt with President Vladimir Putin crossed out in red at a protest in Barcelona. Credit: Getty Images)

Why is private tutoring becoming so commonplace? In London it is estimated that 50% of schoolchildren have a tutor at some point. In Hong Kong, that figure is much higher. What impact does tutoring have education systems around the world? And does it entrench inequality? Mike Williams hears from academics, tutors and the students they teach. (Photo: School teacher and student high five in a classroom. Credit: Shutterstock)

In some countries, about 10% of their population suffers from a food allergy. What is going on? And why do an increasing number of people believe they have an allergy when they don’t? Mike Williams asks how the food industry has responded to this growing fear of food and whether developing nations will end up with the same levels of affliction. Produced by Rosamund Jones (Photo: Food restrictions written in chalk on a blackboard, gluten, nut and dairy. Credit: Shutterstock)

The bicycle - and cycling - started out as somewhat of a faddish leisure pursuit, largely the preserve of middle-aged and wealthy men. Yet it quickly became the world’s most popular means of transport and remains so to this day. So what lies behind its mass appeal? Author and life-long cyclist Rob Penn, helps us chart the cultural and social impact of the bicycle. From helping to widen the human gene pool to blazing a trail for the women’s movement. ‘It’s like learning to ride a bike’ is a common phrase across the globe for ‘once learned, never forgotten’. But what does this suggest about the human body and cycling? Many people describe it as meditative and calming, but what if cycling could actually have a therapeutic effect on those suffering from serious medical conditions? Dr Jay Alberts works at the Center of Neurological Restoration at the Cleveland Clinic in Ohio, USA, and has recently been looking into the impact of cycling on the symptoms of Parkinson’s disease patients. We hear about his surprising results. Finally, in the West cycling has become more of a lifestyle choice than a means of transport, but what about in countries like India? We hear from a hardy cyclist who regularly braves the streets of Old Delhi. (Photo: Cycling guide Arpita Sinha leading a bike tour through the streets, and ditches of Delhi, India)

Sneaker, trainer call them what you will. How did this product of the industrial revolution and a rising middle class become a global fashion item worth tens of billions of dollars a year? Especially when 85% of the purchases are never intended for its original purpose, health and fitness. Join Mike Williams for the Why Factor on Sneakers. Produced by Julie Ball (Photo: A man looks at a collection of sneakers in the window of a shopping mall, in the outskirts of Sao Paulo, Brazil. Credit: Getty Images)

Every week, hundreds of millions of people around the world surrender their emotions; leave them - for a while - in the hands of strangers. They might face dejection or, with luck, jubilation. The US National Basketball association say that less than 1% of fans globally will ever watch a game live. While the Premier League is played in England and Wales, almost half of the fans (470 million of them) live in Asia and Oceania. Mike Williams explains why sports fans do it. (Photo: Sports fans pictured during a football match waving their flags. Credit: Getty Images)

Hundreds of millions of us bear the stress and boredom of the same journey day in day out - the commute. For some it is a time of reflection while for others it is a time to turn the air blue with howls of frustration. Why does commuting make us the people we are and how? (Photo: Rush hour traffic in Nairobi. Credit: Abdinoor Maalim)

From Stone Age caves, to the buildings of Pompeii and on the walls of our modern cities we find evidence of a very human – and ancient – urge to leave a mark. Why? Mike Williams joins the artists at a Graffiti competition held in London and talks to Art Historian Richard Clay, professor of Digital Humanities at Newcastle University. This still illegal activity has gained a more acceptable face in the growth and popularity of street art, but in many countries, graffiti writers still risk their lives to paint political messages on public walls. Researcher Rana Jarbou has been documenting Graffiti in the Arab World since 2007. She reveals the role it has played in the war in Syria. Graffiti can be political and artistic, but sometimes it is as simple as scratching names and love hearts into desks. For four years Quinn Dombrowski took photographs of the Graffiti left on the study desks of The University of Chicago’s Library. The scrawled messages are an insight into the emotional lives of the students there. Finally, back in London at the Graffiti competition, Mike picks up a spray-can and has a go himself. (Photo: The letters TWF graffiti sprayed on a wall. Credit: Mike Williams)

They are human and inanimate, beautiful yet disturbing; made for children but collected by adults. From the rag dolls of Ancient Egypt to the mass produced plastic fashion dolls of today, they have existed in almost every culture. Traditionally, they have been used to teach young girls to dress well and look after others. So are they still relevant in a world where women are taking on different roles in the home and the workplace? Mike Williams meets collectors from Syria and Switzerland. He looks at the evidence that playing with dolls develops children’s social skills, and hears how a South African maker was told ‘black dolls will never sell’ in her country. Produced by Hannah Moore (Photo: Dolls faces. Credit: V&A Museum)

Tea comes in many guises - milky, sweet and spicy for those in India. The Chinese drink it as nature intended green with no milk and strong with two sugars for the average British builder. So how did this Asian leaf conquer the world to become the second most consumed drink after water? Mike Williams slurps and sips his way through this cup of calm to find out how this unassuming shrub conquered the world. (Photo: Preparations for the Chinese Tea Ceremony, at Chaya Tea House, London)

Some of us are content to surrender our personal space to serve on a submarine, while some of us struggle with claustrophobia. As we become more urban and the global population increases, we have to get used to having less space but some architects say we need more of it because it boosts our sense of wellbeing. Why do we have such a complicated relationship with the space we live in? (Photo: Dense cityscape of office buildings in Hong Kong and China. Credit: Shutterstock)

The UN proclaimed its Universal Declaration of Human Rights in 1948, after the horrors of World War Two. But they are far from universally upheld. Yecenia Armenta Graciano’s right not to be tortured was grievously violated in Mexico, when she was beaten, suffocated and sexually assaulted to sign a confession. Yet Human Rights are being used in an increasingly wide range of legal cases, whether to force governments to provide food for the poor, or to cut CO2 emissions to help avert climate change. So what are they, how are they evolving, and what if one person’s human right clashes with that of another? Mike Williams talks to philosopher and law professor John Tasioulas of Kings College London; international law scholar and former UN rapporteur Philip Alston; Dutch lawyer Dennis van Berkel of the environmentalist organisation Urgenda; and India Supreme Court lawyer and human rights campaigner Vrinda Grover. (Photo: Yecenia spent three years in prison since she was tortured to sign a confession for a crime she says she didn’t commit. Credit: Amnesty International)

To mark the centenary of World War One, Mike Williams explores the meaning of sacrifice. We often talk of military sacrifice - young men and women, giving their lives for a higher cause. The “ultimate sacrifice”. Countless acts of bravery on the battlefield have ended in death. Some are remembered, many are not. But is that sacrifice? Or, is there a darker side to be considered - not the willing self-sacrifice of a soldier, but a soldier sacrificed? And have we, as one philosopher suggests, misunderstood the meaning of sacrifice completely? (Photo: A flower appears alongside the Vietnam Veterans Memorial. Credit: AFP/Getty Images)

Why do people give their lives for a nation? For a cause? As the world marks the centenary of the First World War, bereaved families reflect on the sacrifices made by their loved ones. What is the true nature of modern sacrifice? Presented by Mike Williams Produced by Ben Crighton (Photo: Poppies pegged on a wall bearing the names of soldiers who lost their lives in World War One. Credit: Philippe Huguen/AFP/GettyImages)

It’s something that will come to all of us. So why is it so hard to talk about death? Mike Williams meets a British doctor facing her own mortality and another in India who wrestles with telling her patients the bad news. Produced by Smita Patel (Photo: Four gravestones in a graveyard. Credit: Shutterstock)

We trust them with our deepest secrets, and use them to preserve our memories. They’ve been hidden, destroyed, and read without permission. Mike Williams talks to people who write diaries, and the historians on a mission to "rescue" the diaries of normal people. Produced by Hannah Moore (Photo: A handwritten page from a diary. Credit: Mike Williams)

Mike Williams asks why do we travel? Why do we leave the comforts of our homes to go to other places? Psychology has shown that travel - even just thinking about other countries - broadens our minds and makes us more creative. But we travel for many reasons, from acquiring memories, to seeing how other people live, even to build or re-invent our identities. And then there are those, like P. J. O’Rourke, who claim to hate travelling and prefer to stay home. Though it turns out he actually likes tourism, just not tourists. Mike also talks to South African travel writer Sihle Kuhmalo, Stanford Travel bookshop senior buyer David Montero, and psychologist Corinne Usher. Produced by Arlene Gregorius Photo: An international traveller arrives at an airport. Credit: David McNew/Getty Images

For most of us it is a sanctuary. But some people have no home at all, while for others it can become a place of terror and pain. What is home and why is the notion of home so deeply embedded in us? Mike Williams finds out how we shape our homes and how they shape us, how they reflect and reveal our personalities. (Photo: A child's drawing of a house. Credit: Shutterstock)

We use encryption every day - in our bank transfers, on our mobile phones and whenever we buy anything online. Yet what is it and why is it so important? Mike Williams explores cryptography from the Roman Caesar Cipher to modern day computer encryption. Classified as a munition in the USA until the late 90s, lawyer Cindy Cohn recounts the court case she fought which helped put computer encryption into the public’s hands. Science writer Simon Singh talks us through some the mathematics behind the ciphers and Andrew Clark, a specialist in Information Forensics details the darker side of encryption, through its uses in crime. Encryption also plays into our obsession with secrets, puzzles and hidden messages. We hear from a fan of the electronic duo, Boards of Canada, who obsessively followed a trail of encrypted clues left by the band in 2013. Finally, encryption lies at the heart of the debate about national security and individual privacy. We hear from an anonymous contributor from Pakistan where the use of encryption is restricted. (Photo: Encrypted icon of a padlock and its keyhole. Credit: Shutterstock)

The journalist, author and Olympian Matthew Syed blew it big time at the Sydney 2000 games. Despite a GB medal prospect in table tennis, he was thrashed by an opponent he had beaten many times before. He choked. Ever since, he has been keen to understand why sometimes the brain robs an individual of the ability to do routine tasks - in his case to hit a ping pong ball on the table. You do not have to be a world class sportsman to choke. Think of that job interview you fluffed or that wildly attractive person at a party that left you unable to do what you do every day - speak coherently. Matthew explores the neurological and psychological trajectory of a choke. People from the worlds of sport, business and entertainment all feature in this examination of when we fail to do what comes naturally to us. (Photo: A man loses at a table tennis match. Credit: Shutterstock)

How would you describe your nationality and how much does it matter? When did we start defining ourselves by where we are from and why? And how does our nationality affect who we are? The concept of nationality, historically very specific, is becoming increasingly fluid. More and more people: for economic reasons, for love and increasingly to escape conflict, leave the countries they were born in. Mike Williams explores what nationality means to us today by attending a British Citizenship ceremony in London. He speaks to the new citizens from all over the world, to find out why they wanted to become British and to discover how that decision has affected their own personal sense of nationality. He finds out about the history of the modern ‘nation state’ and considers the sporting world where athletes often compete for a different country from the one they were born in. Finally, what is it like not to have a nationality? Mike speaks to two men who have spent their lives stateless due to the partition of India in 1947. Produced by Rose de Larrabeiti Photo: one of the new Citizens getting their certificate confirming their new British Nationality. Credit: Click Print Photos

We all use cash - notes and coins - but with the increasing popularity of transacting by other methods, mobile phone, debit cards, do we still need cash? Some countries in northern Europe such as Sweden and Denmark are working towards a cashless society within the next 10 years. But what about those who are unable to open a bank account, the low waged, the homeless? Although it is argued that getting rid of large amounts of cash would reduce both large and small scale crime, others argue that it is an inalienable right for a citizen to be anonymous, something that is impossible with a debit card or using mobile money which can be traced. Mike Williams asks is cash still king and if so why? (Photo: Various world currency in a green money box. Credit: Shutterstock)

Some people actively embrace risk by jumping out of aeroplanes, scuba-diving or motor-racing. But we all face risks every day just by eating, drinking, walking and driving – simply going about our daily lives carries all sorts of unseen threats. And yet for some reason we often misperceive these risks. We are not very good at calculating things on which our lives may depend. Why is that? Risk-averse Mike Williams speaks to some risk-takers to find out. (Photo credit: Mohd Rasfan/AFP/Getty Images)

The chilli pepper is a work of ‘evolutionary elegance’. Its complex chemistry can fool our brains. Why do we eat something that causes us pain? Mike Williams explores the origins and history of chillies, thought to be the hot and humid climates of Bolivia and northern Brazil before being spread through the world by Portuguese colonists in the 15th entury. He finds out that ancient chillies were not hot. Dr Josh Tewkesbury from the University of Washington explains why the chilli pepper developed heat and why human beings are one of the only mammals in the world to actually enjoy eating them. We unlock the pungency and flavour of chillies in curries with chef and writer Roopa Gulatti. And we uncover their power and punch in powder and pepper spray with Dr Anuj Baruah, a biotechnologist in the north-eastern state of Assam, India, who extracted the chemical compound inside the chilli for India’s ministry of defence. Award winning science writer and journalist, Deborah Blum gives her analysis of the chemistry inside the chilli and its development to explain why she thinks that plants like chillies are ‘formidable military machines’. Finally, Mike tastes one of the world’s hottest - the bhut jolokia - also known as the ghost or poison pepper. Produced by Nina Robinson (Photo: A selection of chillies)

Are some people simply more visual than others? And, what do we reveal through our drawings? Drawing is something we all do unselfconsciously as children before we learn to write. It is a form of expression that goes back 40,000 years and began on the walls of caves. But why do we draw? Is it to make our mark on the world, to decorate our surroundings, or is it a way of communicating with others when words fail us? Lucy Ash talks to Stephen Wiltshire, world famous for his incredibly detailed pen and ink cityscapes; to Rebecca Chamberlain, a psychologist now at the University of Leuven in Belgium who is studying art school students to try and understand how people get better at drawing; to David Hockney renowned for his both his traditional draughtsmanship and his enthusiasm for new technology and to Lizzie Ellis, who comes from a remote community in central Australia and draws with a stick, telling stories through her traditional form of Aboriginal women's art. And at the London charity Kids Company, Arts manager Jebet Mengech encourages children to express themselves with pencils, crayons and felt tips using drawing to reveal problems in the children’s lives. (Photo: A student in a life class at the Royal School of Drawing)

Why did beards evolve and what is the point of them? Evolution may have decided they make a man more manly and can attract the opposite sex but many women are divided in their opinion of the beard. In some religions and cultures a beard is sacrosanct whilst some societies remain hair free. Should you shave them, trim them or grow them to extraordinary length. Mike Williams visits the world’s oldest barber shop to find out the secrets of a close shave and a tidy beard. (Photo: Men participate in a bearded Competition. Credit: Johannes Simon/Getty Images)

From its early days as work-wear for gold-miners and cowboys in the US, denim has transcended its origins, becoming a global fashion item. Mike Williams explores the appeal of a pair of blue jeans and the history of this simple garment. Once a symbol of youth rebellion, it is now common around the world - worn by men and women, old and young. From cowboys to the catwalk, how did denim come to dominate? (Photo: Blue jeans hanging in a clothing store. Credit: Shutterstock)

The Y chromosome. What makes a boy a boy? In this programme we put the Y chromosome under the microscope. We find out how it transforms a female embryo into a male one. We discover what it can tell us about the differences between men and women. We speak to a teenage boy who has not just one Y chromosome but two. And we meet the scientist who turned a female mouse male. (Photo: X and Y chromosome on a black background. Credit: Shutterstock)

Television is beamed into our homes through a proliferation of channels and devices. TV has become an integral part of our lives, all over the world, in just a few short decades. Why has TV taken a grip on us which has never weakened? It influences our politics, our cultural attitudes and social perceptions. Does it mainly distract or engage us? Presenter Mike Williams finds out about TV’s humble origins with the grandson of TV inventor John Logie Baird, and runs through some of television’s most viewed moments. We feature one of the biggest reality TV stars in the Middle East, winner of Arab Idol 2013 singing contest, Mohammed Assaf, who shares his thoughts on the medium. TV, once tightly controlled, has escaped into the world and continues to change our societies in unimaginable ways. (Photo: A wall of 750 television screens at an exhibition celebrating 50 years of television broadcasting, in Melbourne, Australia. Credit: AFP/Getty Images)

Stamps, coins, sea shells, wine - the list of things that humans collect is endless. But why do people do it? What does a collection of inanimate objects bring to our lives that other things do not? Are people attracted by the thrill of the chase, the pleasure of possession or the control in acting as the custodian of precious things? Mike Williams talks to an eclectic group of collectors in search of some answers. Roman and Maz Piekarski have spent the last 50 years building up a collection of some of the world’s finest cuckoo clocks. When Lisa Courtney was bullied as a child she gained comfort in building her collection of Pokemon toys.Seventeen-year-old Tushar Lakhanpal started his pencil collection at the age of three and when David Fulton sold his business to Microsoft in the 90s his new found wealth allowed him to pursue and acquire one of the finest collections of rare instruments ever assembled. (Photo: Roman and Maz Piekarski have been collecting cuckoo clocks for the last 40 years. BBC copyright)

Why do we use jargon - the deliberate obfuscation of language? Or in other words, saying things in a way that makes it difficult to understand. George Orwell, in the early 20th Century, hated this ‘inflated style’ of writing and there have been many attempts to get rid of it. In the 1940s Sir Ernest Gowers from the British Civil Service wrote a book - Plain Words - which has been reprinted again and again, most recently by his great grand-daughter who tells presenter Mike Williams why jargon is just as bad today as it ever was. It has been blamed for pulling the wool over the eyes of the general public and it’s the same all over the world. (Photo: The classic work Plain Words, originally written and published by Sir Ernest Gowers who wanted to see the English language free of jargon. BBC copyright)

In stories, cartoons, advertisements and our everyday lives, we project human thoughts and emotions onto animals—and claim their strength and style for ourselves in the brand names of cars and cosmetics. Why do we do that, and what do we get out of it? Can we ever know what animals really feel? And are we as different from other species as we like to imagine? Maria Margaronis meets the furry fandom, who put on 'fursonas' and cartoon-like animal costumes to meet and socialise. Neuroscientist Bella Williams up-ends some assumptions about animal brains and explains how to read a mouse’s facial expression. Children’s author Michael Rosen sportcasts an insect race. Farmer Helen Reeve reflects on how she feels about eating her own cows. And, historian Harriet Ritvo poses a thornier question - what makes our species think we are secure in our dominance over the natural world? Produced by Sue Davies (Photo: The furry fandom and their fursuits at a gathering of animals in a pub in the east of England. Credit to: Harlequeen)

From clowns to tight-rope walkers, fire-eaters to elephant trainers, the modern circus has been around for centuries. Mike Williams explores its origins and asks why it appeals to adults and children around the world. As part of the programme, Mike learns how to do the flying trapeze, takes tips from an acrobat at the Moscow State Circus and hears from a clown from Cirque Du Soleil – who has a rather alarming story about audience participation. Mike also talks to a lion trainer with the biggest animal act in the world and finds out what happened when he accidentally fell on one of his big cats. Produced by Sally Abrahams (Photo: Martin Lacey jr. performs at The Circus Krone Show in Munich, Germany. Credit: Hannes Magerstaedt/Getty Images)

Freud thought daydreaming was not a useful activity, and many teachers across the world have been heard to say “stop daydreaming” to their pupils. But it seems to have redeeming purposes. Opera singer Noah Stewart explains how he uses daydreaming as a way to prepare himself for the stage. And Peter Moore, an IT contractor who was held hostage in Iraq, describes how his mind began to fill the emptiness of his days with dreams of escape and comfort. While daydreaming may be universal across cultures, there seem to be many differences in in how we do it - from playful vivid fantasies, to problem solving, to obsessing. And is daydreaming a taboo subject? We explore why it’s not discussed. (Photo: A young girl lies on the grass daydreaming. Credit: George Marks/Retrofile/Getty Images)

The desire to live is strong in us humans. But it’s not always enough. Sometimes people fall so low that they can see only one way forward. And every year, across the world, around a million people take their own lives. Why? The answers are as complex and numerous as the people themselves but, often, there are common features… and, by understanding these, it may be possible to help them. Presenter: Mike Williams Producer: Ben Carter If you’ve been affected by this programme and would like to get help please visit: www.samaritans.org or www.befrienders.org (Photo: Steve Mallen whose 18 year-old son Edward took his own life in February 2015. BBC Copyright)

At the mercy of people smugglers, they are transported by night, walking overland and travelling by sea, hiding during the day. These are journeys that are long, costly, and sometimes deadly. Mike Williams follows the journeys of 'Howram', a Kurdish man who fled Saddam Hussein’s Iraq, and ‘Hatem’, a Syrian, who walked through 14 countries before reaching the UK. Both journeys were long and perilous and the men left countries and families they loved. They speak of the smugglers who transported them from the Middle East and into Europe and the brutalising experiences they went through. We hear from the acclaimed Palestine Syrian musician and composer, Abo Gabi, who fled the besieged Syrian city of Yamouk, first for Beirut in Lebanon, then for Paris. The smugglers, he believes, are the new warlords. He asks what home means when your city has been destroyed and your family and friends have been tortured and killed? Produced by Angela Robson (Image: Hatem, who fled Syria and walked through 14 countries transported by different groups of smugglers. Photo: BBC copyright)

More than four billion people live in countries which retain the death penalty. Mike Williams asks why more than 50 countries around the world still execute certain criminals. What is the death penalty for and how is it carried out? He talks to a former American prison officer who presided over 33 executions in the US state of Ohio and asks whether he has any regrets. He also speaks to a Nigerian former death row prisoner who escaped the gallows with just seconds to spare. And he hears from a lawyer in Indonesia where two convicted Australian drug traffickers are awaiting execution. Produced by Caroline Bayley (Photo: The Texas death chamber in Huntsville, Texas. Credit to: Joe Raedle/Newsmakers)

We look inside the brain to find out why we lose our memories, and why there are some things we can not forget. We talk to a neuroscientist seeking to unlock the secrets to how we remember things. And, the woman who can’t forget an episode that occurred over 70 years ago. (Photo: Woman sits behind the driving wheel, forgetting something. Credit: Shutterstock)

Why do people all over the world enjoy stories about criminals and the people who bring them to justice? And what do the detective stories of a particular time or place reveal about that culture? From the consulting detective Sherlock Holmes to new South African crime fiction, Helen Grady investigates. (Photo: The shadow of fictional detective Sherlock Holmes. Credit: Peter Ruck/BIPs/Getty Images)

In every city in the world there is a viewing platform where you can gaze down upon the place from on-high. But why do we like to build tall and be high – what is it about standing tall and defying gravity that matters so much? Are Skyscrapers simply about vanity or are there practical and even spiritual reasons why we want to build so high? Mike Williams ventures up the Shard, the tallest building in London, with its architect Renzo Piano. He talks to Blair Kamin, Architecture Critic at the Chicago Tribune – the city that brought us the skyscraper, as well as experts Daniel Safarik, from the Council on Tall Buildings and Urban Habitat and Dr. Phillip Oldfield, from the University of Nottingham. Produced by Wesley Stephenson (Photo: The Sears Tower rises above the skyline in Chicago, Illinois. (Photo by Scott Olson/Getty Images)

Why do the rich want to get richer? Why when you’ve got a million or even a billion do you want more? Mike Williams asks a multi-billionaire and a multi-millionaire what drives them to keep making more money. He also speaks to a banker, who looks after the wealthy and a football agent, who represents high paid players and tries to discover whether the rich are different from everyone else. (Photo: Image of a superyacht believed to belong to a Vodka Tycoon. Credit: Phil Walter/Getty Images)

Why do some people refuse to be rich? The lottery winner who gave it all away, the vegetable stall holder who never allowed herself to accumulate wealth, and the businessman who sold his big house and flashy car to set up a Christian project in Uganda tell their stories. (Photo: Hands holding money. Credit: Momentstock) The music in this programme has been changed from the original broadcast.

We’re rarely far away from a device telling us the time, yet sales of luxury watches have never been higher. Mike Williams explores why the seemingly obsolete technology in mechanical watches is still highly desirable, and what wearing one says about its owner. (Photo: Pocket Watch. Credit: Wolfman57 Shutterstock)

A recent study has shown that sad music has become increasingly popular, but why do people choose to listen to it, and what goes on in the brain and the body when they do so? Helena Merriman speaks to Japanese pianist and music researcher Dr Ai Kawakami who has some surprising answers about some of the positive feelings people experience when they listen to sad music. American writer Amanda Stern tells Helena why she regularly listens (and cries) to sad music and British composer Debbie Wiseman, known for her moving TV and film scores, explains what makes a piece of music sound sad. You’ll also hear pieces of sad music suggested by BBC listeners from all over the world. (Photo: A woman with headphones on, listening to sad music. BBC copyright)

Mike Williams asks why do we fly flags? They have many uses, from identifying symbols to signalling tools. But why a piece of cloth? Because it moves in the breeze, and movement catches the eye. The first flags were used by warlords in China, as China wove silk. Mike goes to the National Maritime Museum in Greenwich to find out about the many uses of flags in merchant fleets and the navy, and hears from the designer of the new South African flag that it was all done in such a rush that his sketch had to be faxed and coloured in at the other end, to get the approval of Nelson Mandela who happened to be in a meeting in another city. Mike also talks to a German artist who replaced the two Stars and Stripes on the Brooklyn Bridge with white versions, and to the Russian who planted a titanium Russian flag on the floor of the Arctic ocean, to claim it for his country. Produced by Arlene Gregorius. (Photo: Faithfuls with flags of different countries gather at a beach. Credit: Tasso Marcelo/AFP/Getty Images)

Who are you loyal to? Your family, partner, employer? Why? Mike Williams talks to people whose loyalty has been challenged – from the wife of an unfaithful husband, to a doctor who blew the whistle on her employers. Are we ultimately only really loyal to ourselves? A Catholic priest argues that it is better to be committed to values than loyal to superiors. Mike also hears how loyalty can be created to get people to kill – such as in the military. (Photo: A loyal dog looks up to his master. Credit: Christopher Furlong/Getty Images)

From the first photographic portraits captured in the 1830s to the “selfies” of today, we seem fascinated by images of the human face. Mike Williams asks if it is simple vanity or something deeper; perhaps an attempt to learn how other people see us or a desire to capture something of ourselves that may live on when we are gone. Produced by Smita Patel (Photo: Old black and white and sepia photos at a flea market in Paris, France. Credit: Shutterstock)

The moon has fascinated humans everywhere and for all time. Why? Mike Williams explores the moon in culture, how it affects life on Earth and he asks Alan Bean – one of the handful of people who have walked on it – what the moon is really like. Produced by Richard Knight Image shows a full moon as seen from the sky at night. Credit: AFP/Getty Images

People have fought for honour and died for it. People have murdered others because of it. Why is this notion so powerful and so lasting? In this edition we examine the honour-codes of the Japanese samurai, we explore honour in the works of William Shakespeare and look at the persistence of so-called honour killings. Produced by Ian Muir-Cochrane (Photo: A man dressed in a Samurai costume and helmet during a festival in Japan. Credit: Buddhika Weerasinghe/Getty Images)

For centuries perfume has been used to show status and wealth, for medicinal and for religious reasons and the global business is now worth tens of billions of dollars a year. So why do we still perfume ourselves? What image are we trying project when we use a fragrance that emanates from our bodies and permeates the air? Mike Williams talks to a historian, an archaeologist, a 'nose' and a business analyst to find out. He also learns how to make Eau de Cologne. (Photo: A craftswoman works on a perfume bottle at a fragrance workshop in Paris. Credit: Miguel Medina/AFP/Getty Images)

Why do we share? What makes it different from giving? And what does it have to do with strategy and impulse control? Mike talks to the scientist Nikolaus Steinbeis who found out which region of the brain is active when we share and why small children have problems with that. He visits the Redfield Community in the north of London, where over 20 people share a household and he discusses with a young 'couchsurfer' and a software specialist from the Linux foundation about the pros and cons of sharing. (Photo: Two teenage girls lying on the grass sharing headphones. Credit: Shutterstock)

We are all born naked, yet there is a taboo about displaying naked bodies in public. Societies around the world have established conventions about who may see what, when and where. So why does the naked human form provoke such strong reactions? A fully-clothed Mike Williams visits a life drawing class, speaks to the founder of a topless protest group, and hears from an academic about how the former East German government tried, but ultimately failed, to ban public nudism. (Photo: Tourists look at David by Michelangelo in Galleria dell'Accademia in Florence, Italy. Credit: Lornet/Shutterstock)

Why do we cook, and not just eat raw food like all other animals? Jo Fidgen hears that our ancestors first started to cook about two million years ago, and the advent of cookery coincides with our developing bigger brains, and smaller guts. Harvard primatologist Richard Wrangham argues that it was cooking that led to both these developments, as cooked food is easier to digest, and allows the body to absorb more calories from the food, thus making it possible to fuel a bigger brain. So cooking made us human. Historian Felipe Fernandez-Armesto adds another dimension to this argument. He says cooking led to communal mealtimes and the move from solitary scavengers to organised groups - and thus the start of human society. Nowadays we also cook because we enjoy it, or to show our affection for those we cook for. But there are other, more basic reasons for cooking, such as making food safe to eat. Jo Fidgen talks to primatologist Richard Wrangham, food historian Felipe Fernandez-Armesto, nutritionist Daniel Commane, and Itamar Srulovich and Sarit Packer, a couple who run a Middle-Eastern restaurant. (Image: A chef prepares food at a wine and food festival, New York. Credit: Noam Galai/Getty Images for NYCWFF)

The disappearing world of the handwritten letter – a letter of advice on love from a father to a son, letters to a man who spent decades on death row in America, and letters between lovers. How will we understand our family history now that there is no box of fading letters in the attic? How will we remember old loves and times gone by? (Photo: ‘The Letters’ (detail) by Simone Sandelson used with her permission. Credit: Mike Williams)

Jo Fidgen asks why we read, or write poetry, as opposed to prose? What can poetry do that prose can’t? And why do we respond to poetry in a way that we don’t respond to prose? Jo talks to award-winning American poet Jane Hirshfield, to Cambridge cognitive neuroscientist Usha Goswami, to Brazilian “cordel” poetry expert Paulo Lumatti and to Rachel Kelly, author of Black Rainbow, who found poetry helped her recover from severe depression, and now reads poems in workshops with prisoners and others. (Image: A poet writes before a poetry performance at a club in New York. Photo by Spencer Platt/Getty Images)

How we remember the dead, and why does it matter? In this special edition of The Why Factor Mike Williams starts with the promise of so many nations never to forget the death and suffering of the First World War, to explore how the dead have been remembered around the world and through the ages. Produced by Ben Crighton (Image: Ceramic poppies covered in rainwater at the Blood Swept Lands and Seas of Red evolving art installation at the Tower of London Credit: Chris Jackson/PA Wire)

How do we remember the dead and why does it matter? Mike Williams considers the promise of so many nations never to forget the death and suffering of World War One, and explores how the dead have been remembered around the world and through the ages. Produced by Ben Crighton Image: Ceramic poppies covered in rainwater at the Blood Swept Lands and Seas of Red evolving art installation at the Tower of London Credit: Chris Jackson/PA Wire

Why has the game endured over more than 1500 years and how has it mirrored politics and changes in society? We speak to Chess federation president Kirsan Ilyumzhinov, chess pupil Diana Davletova, women’s chess champion Judit Polgar, Grande Master Dan King, Artificial Intelligence expert David Levy, chess historian Marilyn Alom and chess author Dave Edmonds.

A knot in the stomach, a blush to the face, a wish that the ground would swallow us up and end our misery. We’ve all experienced embarrassment and wished it would never happen again. But why do experience these feelings and what do they mean? Mike Williams asks psychotherapist Philippa Perry to explain embarrassment and what it says about us and how other people see us. Dr Jieyu Liu, deputy director of the China Institute at the School of Oriental and African Studies in London, tells Mike how the different generations in China view the reasons for embarrassment and how far it differs from “loss of face”. She also discusses how it is possible to feel embarrassed for “the nation”. And former top cricketer and sports commentator, Ed Smith, reveals how sportsmen and women deal with embarrassment and whether it can be managed for better performance and results. Produced by Simon Coates (Image of a woman looking embarrassed. Credit: Shutterstock)

Karma is a fundamental part of many eastern based religions including Hinduism and Buddhism. It is commonly interpreted as action. Those who believe in it say their past actions influence their life today and their future actions will have positive or negative repercussions in this life or the next. What impact does this belief have on individuals and communities? Does it encourage fatalism or is it a guide to improving your life? And does collective karma exist? The programme talks to an Indian guru Swarmi Sukhabodhananda, buddhist agnostic Stephen Batchelor, scientist Jim al-Khalili, associate professor of religious studies Elizabeth Harris and journalists Mark Tully and Mary Finnigan. Produced by Bob Howard

Walk down any street in any town or city anywhere in the world and you’ll be bombarded by brands screaming out to be noticed. It’s the way businesses get us to believe in their product, and to ultimately sell us stuff, but where does this concept of brands and branding originate from, and why do we place such trust in belief in what they stand for? Look at every product these days and you’ll see how branding works. From those double golden arches, to that little green fruit, to the small tick that urges us to just do it, everything now is designed in such a way that makes us believe in the power of the product, but why? Journeying through the history of brands and branding, moving right the way through to the modern day, Mike Williams talks to those involved in branding. Is it an art? Is it a science? Is it a fair relationship, or do marketers have consumers at a disadvantage when it comes to getting us to believe in their product? Produced by Johny Cassidy (Image: A man looks at a shop window display as he passes by a clothing store. Photo credit: Tim Boyle/Getty Images)

Why is it so hard to pin down what we mean by it? The Greeks called it a gift of grace, but it’s been widely interpreted ever since. Why do we disagree so strongly about who has it? And are its traits inherent or can they be learnt? The programme explores the magnetic appeal of politicians, sports stars and religious leaders. And asks whether it’s possible for people to 'learn' charisma. Produced by Bob Howard Image: Hand holds a plasma ball with magenta-blue flames, represents personal magnetism. Photo credit: Shutterstock

History and mythology are filled with great rivalries, the foundation of Rome by the twins Romulus and Remus, brothers first, then enemies. Rivals have spurred each other to create new technologies… think of Steve Jobs and Bill Gates. They’ve given us great sport as well: Hamilton and Rosberg on the race-track today, Evert and Navratilova on the tennis court in the 1970s and 1980s, the Yankees and the Red Sox for more than a century. The rivals have given us whole new industries and music that defines a generation. What is rivalry? In this episode of the Why Factor we’ll hear about some of history’s greatest rivals from business, technology and sport, and explore the creative and destructive side of one-upmanship. Produced by Gemma Newby (Image of a Friendship and Rivalry Justice Scale on a white background. Photo credit: Shutterstock)

Why would someone risk their life for a stranger? Why would a 54-year-old Englishwoman leave her home, her son, her grandchildren and travel nearly 5000 miles (8000 km) to the Ebola hot-zone of West Africa? Why did Cokie van der Velde do it twice? And why is she doing it again? The deadly Ebola virus has spread through West Africa and threatens to spread further. It has claimed nearly 2,500 lives. The World Health Organisation says the health crisis is unparalleled in modern times, and that the death toll could eventually be in the tens of thousands. The United States has plans to send up to 3000 troops to help combat the epidemic. On the Why Factor this week, Cokie van der Velde tells Mike Williams about conditions on a Liberian Ebola ward and about the fear she feels as she cleans bodily fluids from the floors and puts the victims into body-bags. It’s an experience which has forced her to reassess her attitude to death - the death of her patients and her own. Produced by Neal Razzell (Image of Cokie van der Velde in Guinea. Photo Credit: Medecins Sans Frontieres)

There are many ways to get involved in politics, so what brings people out into the streets to take direct action against the powerful? Mike Williams looks at some of the surprising motivations behind protest. Producer: Mike Wendling (Photo: Protester wearing a Guy Fawkes mask during an anti-fascism rally in Toronto 2017. Credit: Getty Images)

In the 100th edition of the Why Factor, Mike Williams explores what we have learnt about our very existence. From teenagers and coming of age to retirement, burial and much more along the way. Producer: Helena Merriman

For thousands of years, in every corner of the world, people have been gardening – including in war and in prisons. Helena Merriman explores the peculiar magic of garden and asks why people take so much pleasure in it. She talks to the designer of 58 of China’s public gardens, finds out what swimming mice reveal about the secret properties of soil and hears about the extraordinary lengths one man went to create a garden in Guantanamo Bay. (Image of a Classical Chinese Garden. Credit: Shutterstock)

It’s a regular, if not always a reliable source of news. Without gossip, cafes, bars and workplace water-coolers would often be silent. But why do so many of us feel the need to discuss other people’s lives? Gossiping’s been punished in the past, but it’s big business now and may, Mike Williams explains, even be good for us Produced by Chris Bowlby (Image of two girls gossiping to one another. Credit: Science photo library)

Ghosts have been haunting people all over the world for centuries. But why do they persist in this age of reason? Mike Williams explores the fear and fascination ghosts produce and finds out how our reaction to apparitions has changed over the years. We join a group of ghost hunters in England on a spooktacular tour of a derelict orphanage; Mike meets the cultural historian Dr Shane McCorristine in the birthplace of the Victorian ghost story; and the psychologist Professor Christopher French explains the mind’s capacity to produce hallucinations. (Image of a ghostly woman standing by the window. Credit: Shutterstock)

From the Europe of the Middle Ages to the wired world of today, The Why Factor this week looks at chastity – a complicated subject, tangled up with morality and modesty, with politics and religion, and with the role of women through the ages. Mike Williams speaks to, among others, an American campaigning for abstinence in US schools and a nun for whom chastity is an important part of the job. He examines chastity chosen, and chastity imposed. Produced by Nina Robinson Picture: Chastity belt, Credit: BBC

The Pilgrimage is one of the most popular and collective human activities, and continues to grow in size. Tens of millions of Hindus bathe in holy waters at the Kumbh Mela. Jews from around the world make their way to the Western Wall in Jerusalem. Islam has the Hajj and Christians have walked the same paths for centuries. Others find themselves on a pilgrimage for very different reasons. Mike Williams finds out why. (Photo: The Grand mosque and the Kaaba in the holy city of Mecca. Pilgrims pelt pillars symbolising the devil with pebbles to show their defiance on the third day of the hajj to mark Eid al-Adha or the Feast of the Sacrifice. Credit: Fayes Nureldine/AFP/Getty Images)

Why do we go on long walks? Aside from the seemingly obvious health benefits of exercise, what is it about walking which has had such long-lasting appeal? The German film director Herzog described walking as “spiritual” whilst Charles Dickens used walking to plot his novels. From the German tradition of the wandern to urban street walking, it seems we’ve always gone on long walks for reasons other than necessity. Why? Mike Williams puts on his walking boots and goes in search of answers. (Photo: Hikers walk along a path as what remains of the Findelgletscher glacier near Zermatt, Switzerland. Credit: Getty Images)

The moon has fascinated humans everywhere and for all time. Why? Mike Williams explores the moon in culture, how it affects life on Earth and he asks Alan Bean – one of the handful of people who have walked on it – what the moon is really like. Producer: Richard Knight (Image shows a full moon as seen from the sky at night. Credit: AFP/Getty Images)

Why do we say sorry – and what do we really mean by it? Mike Williams explores the apology, from ancient Greece to today’s penitent politicians. Is an apology alone worth anything? Is it just part of a process, leading to action or forgiveness? And can one generation apologise for the actions of another? Producer: Nina Robinson (Photo: A banner reading 'Sorry’. Credit: AFP/Getty Images)

What is coincidence and why do we attach meaning to it? Jo Fidgen hears World Service listeners’ gripping coincidence stories. Some of them are almost unbelievable. But are we simply failing to understand randomness, and the law of truly big numbers? Produced by Charlotte Pritchard (Photo of a young woman with her hands over face. Credit: Getty Images)

Mike Williams presents a special extended edition of The Why Factor on patriotism. He asks what motivates people to serve their country and how this loyalty can be fostered, manufactured and manipulated. Mike investigates the power of patriotism from World War One to the present day – exploring flags and anthems, borders and boundaries, King and Country, God and Empire, and the truths and the myths of the modern nation state. What would you be willing to fight and die for? Produced by Ben Crighton (Image of a veteran soldier standing against a black background. Credit: Getty Images)

On this week’s Why Factor Jo Fidgen meets an Englishwoman who suffers from a rare condition known as Foreign Accent Syndrome which causes her to speak with a French-sounding accent. What can her situation teach us about accents and why they matter? Jo explores why English sounds different across the globe and takes an accent lesson from a Canadian drama teacher. And did you know some animals have accents too? Produced by Laura Gray (Photo: A woman's mouth smiling. Credit: Getty Images)

Why is making eye contact so important? Catching someone’s eyes across a crowded room can lead to a passionate love affair. Yet catching the wrong person’s eye in a bar could lead to a tussle of another kind. Mikes Williams explores why eye contact is an essential part of a baby’s development; how it is used to attract a partner and what our eyes give away about us, which is beyond our control. (Photo: Eyes making contact. Credit: Shutterstock)

The fool – or jester – has been an important, even powerful, figure in many cultures, over many centuries. Why? Mike Williams explores the role of the fool, their place in culture and politics, and asks whether there is still a need for a funnyman who can speak truth to power. (Image: Puppet Clowns stored at the Clown’s Church in east London. BBC Copyright)

Diplomacy - what’s it for and how is it done? We present a user’s guide to the 'great game'. We hear about the tense negotiations and the rows, about the polite language and the secret code words used to deceive opponents. And we hear about cigars and lavish dinners and discover the importance of sandwiches. Presented by Mike Williams. (Image: A mixture of words relating to Diplomacy. BBC Copyright)

Why are we competitive? Is it a natural instinct? Should we nurture competition in our children so they learn that victory is the ultimate goal and that only the fittest survive? Or do we over emphasise the importance of competition at the expense of all else? Jo Fidgen explores why we are so reliant on competition and what it means for our future success. She finds out how hormones affect our competitive behaviour and whether men are always more competitive than women. (Photo: two hurdlers competing against each other at the Shanghai Stadium in China, Credit: Getty Images)

Symmetry is everywhere once you become aware of its presence. We see symmetry all around us; in art, architecture and science, but also in more complex forms, buried deep into the genetic code of nature. Why does symmetry exist and why do we see such beauty in it? Mike Williams talks to the Oxford professor and mathematician Marcus du Sautoy about the fundamental properties of symmetry and how we are sensitive to the order and simple beauty of it. We hear from New York fashion photographer Alex John Beck about his work on symmetry in faces and why we find symmetrical faces attractive. Plant biologist Dr Paula Rudall explains how bees are also attracted to symmetry in flowers. Lebanese composer and musician Bushra el Turk demonstrates the use of symmetry in music and the pleasures we experience when hearing it – and hearing it disrupted, in unexpected ways. (Image: Most flowers have bilateral symmetry which bees are attracted to for pollination. BBC Copyright)

What makes snippets of popular songs go round and round in our heads? Which songs are likely to be earworms or 'sticky songs' and what sort of person is most susceptible to them? If an earworm is driving you mad, how do you get rid of it? And what might the wider mental health benefits be of understanding where the mind goes when we let it off the leash? (Image: Teenager listening to CD’s with headphones on)

Is kissing universal to all cultures? It might be today, but one 19th century African chief’s daughter got a fright when a British explorer tried to kiss her. Do prostitutes kiss? Julia Robert’s character in the 1990 film ‘Pretty Woman’ said no to kissing clients. A former sex worker in London tells us about her experiences. What happens to your body when you kiss? Your pupils dilate, your pulse races - hormones play havoc. Is the first kiss special? Secretive in Egypt, passionate in Ghana, romantic in China, coy in the US - we hear about people's first kisses and what they meant to them. Why do we kiss? There is no single answer, but many bizarre theories: did it evolve from children’s eating habits? Mike Williams investigates. (Image of two women kissing at a festival, credit AFP/Getty Images)

Most people believe in some aspects of luck. Is believing in luck something which can empower us or does it mean we give up whatever control we feel we have over our lives? Mike Williams discusses luck with former professional cricketer Ed Smith, therapist Alexander Anghelou and Cambridge psychologist Mike Aitken. And Mike also visits a casino to meet a reformed gambler. (Image of a Four Leaf Clover traditionally thought to bring good luck. Credit: Getty)

Why do we read horoscopes? On this week’s Why Factor, Mike Williams gets a reading from celebrity astrologer Susan Miller and delves into the history and psychology of horoscopes. He unpicks the complicated relationship between religion and astrology and questions why some of us make important life decisions based on our horoscope while others think it is all nonsense.(Image: Getty)

Why are some people racist and judge others by the colour of their skin? Is it some deep seated fear of the ‘other’ which has roots in genetic and cultural difference or are exposure to artificial factors constructed by politicians and the media to blame? This week's Why Factor with presenter Jo Fidgeon explores the experience of racism around the world and in different societies. She finds out about the personal experiences of racism and how it affects peoples’ everyday lives. She also begins to understand how racism is perpetuated through generations and cemented through institutional racism.(Image: Members of the Knights of the Ku Klux Klan participate in a neo-Nazi rally. Credit: Associated Press)

The programme examines boredom and discovers the history of how it developed as an idea and consequently became a moral issue. Boredom is becoming a fashionable area of academic research where surprising conclusions have been reached about its effects and purpose. And even if today’s hi–tech workplace - or perhaps because of it - boredom is still to be found and presenting challenges as to how to deal with it.Jo Fidgen discusses boredom with historian Dr Tiffany Watt-Smith from the University of London, Professor Missy Cummings, Institute for Brain Sciences, Duke University, North Carolina, USA and a former drone pilot Lt Col Bruce Black. She also submits herself to a boredom experiment with Dr Wijnand van Tilburg a psychologist at Southampton University. BBC archive recordings include Inside Job and Hancock’s Half Hour.(Image of a lady yawning. Credit: Think Stock)

Why do we envy other people? Mike Williams meets a woman who is experiencing severe ‘baby envy’ because she cannot have a child. He explores the role envy plays in literature, whether social media makes us all more envious and if the emotion - often considered dangerously destructive - can sometimes be a force for good.(Photo: A baby wanting the gold cup for herself. Credit: Getty Images)

Dance exists in every culture. It’s thought that humans were dancing before we learned to speak. But why do we have this desire to move, and what are we trying to communicate? Mike Williams explores the idea of ‘muscular bonding’ – that moving together creates communities. He hears how Indian Kathak dance connects body and soul, how a Northern Australian society uses dance to blur gender divides, and how watching others dance makes us move too.Picture: Dancers perform 'Bharatanatyam' on wheelchairs, a classical Indian dance at an event in Bangalore. Credit: AFP/Getty Images

Last names tell a story. Your last name could determine your career. It could decide how easily you move through society or alternatively how hard it could be to get ahead. Some last names grow longer and longer as they carry a family story from generation to generation. Others stagger under a double barrel as partners perpetuate their own last names through their children and a hyphen. So what’s in a last name? A whole lot as Mike Williams discovers in The Why Factor. (Image: A mixture of surnames from around the world. BBC Copyright)

What’s in a name? Each of us has one and it is a fairly fundamental part of us. But what does the name say about us - and about our parents who, in most cases - chose it for us? Why do some names go in and out of fashion? And is the freedom to name our children as we wish a fundamental human right? In the first of two programmes on names, we begin with first or given names. The programme is presented by the solidly-named Mike Williams. (Image: A mixture of names from around the world. BBC Copyright)

Although we assume a natural right to privacy, we readily give it away on our mobile phones and on social media websites. So as technology alters the very definition of what privacy is and the science of surveillance becomes ever more acute, is the idea of privacy little more than a quaint last-century notion? Mike Williams traces its history, and ponders what a society without privacy might look like.(Image: Girls peer through a crack in the door. Credit: AFP/Getty Images)

Why is drinking coffee so compulsive, and controversial? Mike Williams explores the spread of coffee drinking, and why its production, and consumption, matters so much around the globe. He hears about coffee’s dark origins as a mystical drink, its social function in café societies, and its recent spread through trends such as ‘Seattle coffee culture’. Are tea-drinking cultures willing to be converted? And, as producing nations like Brazil, face huge variations in world prices and the long-term threat of climate change, what does coffee’s future look like?(Image: Hands holding coffee beans. Credit: AFP/Getty Images)

Wood is a vital human resource. But trees inspire myths and reverence. So, Mike Williams asks, why are our feelings about trees so mixed? He hears why every human age is a ‘wood age’, why trees are crucial to social life in African cities, why one New Zealander swapped cutting trees for spending nights in them, and why Danes fear global disease and climate change may lose them their mythical ‘tree of life’.(Image: An arborist works on top of a tree at The Royal Botanic Gardens, Kew. London Credit: Getty Images)

In the West, teenagers are commonly perceived as being volatile, moody and often seen as being “trouble”. Why? Well, because they are teenagers. All that growing, all those changes. But in recent years scientists have discovered that changes to the brain, which occur during puberty, make young people less able to control their emotions and result in different attitudes towards risk as compared to adults. Can these changes to the brain explain why adolescence can be such a difficult period of our lives? Or is adolescence a manufactured cultural concept we’ve invented? (Image: Three teenagers smiling. Credit: Think Stock)

Why do we touch each other? And how do different cultures view physical contact in everyday life? Mike Williams explores our least-studied sense and meets a woman who gets her fill of human contact by cuddling people she has just met. (Image: A mother and daughter hold hands. Credit: Getty Images)

Ahead of the Sochi Winter Olympics next month and the controversy surrounding Russia’s anti-gay laws, Mike Williams and a panel of guests discuss homosexuality. Essentially, why does it exist? Is there any evolutionary advantage? And what is the current thinking in the nature vs nurture debate?(Image: A participant unfolds a rainbow flag during a local annual gay pride parade. Credit: AFP/Getty Images)

From sub Saharan Africa to the west coast tribes of Canada to the Mardi Gras of Rio, New Orleans and Venice, masks define realities - of religious belief, of healing power, of theatre and entertainment, of concealment and of memorialisation in death. They have been around as long as humanity and they evoke both fascination and fear. Mike Williams traces the power and culture of masks and asks why we have them and what they mean for us.(Image: A group wearing masks of legendary heroes as they perform a dance in Minhe County of Qinghai Province, north-west China. Credit: Getty Images)

Alcohol has been part of human civilisation for thousands of years. Evidence from pottery residues suggests that people in ancient China may have been enjoying the delights of wine as long ago as 9,000 years. But our attraction to the ethanol molecule may go back much further than that – to a time when our distant ancestors were eating nothing but fruit. So why do we drink the stuff? And why do some people have problems controlling their drinking?(Image: Scenes of debauchery and drunkenness in "Gin Lane and Beer Street" London, circa 1751. Credit: Getty Images)

Running is experiencing an explosion in popularity in the UK and across the world. So why are we running now more than ever - the recession, the Olympic competitive factor, the new social media app revolution, public health awareness, mid-life crises or rising life expectancy? Mike Williams, not exactly a natural runner, tests out these theories and is persuaded to try barefoot running himself.

Why has one of the world’s most important scientists been forgotten? Fritz Haber was the brilliant German Jewish chemist who used nitrogen to help feed billions, but arguably, kill millions. He worked with something without which, we'd all be dead. It's in our DNA and the plants we eat could not exist without it. Find out why with Mike Williams.(Image: Fritz Haber Photo by Topical Press Agency/Getty Images)

Mike Williams finds out how the way we lend and borrow money is changing. He travels to Blackpool to meet 71-year-old Jeannette, whose life was ruined by debt. He speaks to David Graeber, author of Debt: The First 5000 Years, and learns about a ground breaking debt collection service that finds people jobs before asking for their money.(Image: A man holding US $100 bank notes. Credit: Corbis)

Why do men cross dress? Mike Williams interviews Helen, a London Underground train driver, Peter a detective novelist - who prefers dressing as Penny - and Peter’s wife who helps to choose the clothes and decide Penny’s look. He talks to the artist Grayson Perry about the relationship between his art and cross dressing. He also poses the question why is it that western society accepts men in kilts, priests in cassocks but has issues with men in skirts?(Image: Artist Grayson Perry walking down the catwalk during a fashion show, in London. Credit: Getty Images)

Crying emotional tears is uniquely human. We cry over almost anything and for almost any reason – from tears of sadness to tears of joy. Music can induce them, films, stories and television news too. We do not produce tears when we are first born – it takes a few months until we are able to. But once we can, we do it right up until our final days. So why do we cry? Mike Williams traces some of the competing theories of tears with the help of scientists, psychologists, and a historian. He also watches as an actress is made to cry by her acting coach.(Image: A tear drops falls from a person's eye . BBC copyright)

Why do tens of millions of women all over the world choose to walk around in high heels? Where did the fascination with elevated footwear come from and what do they tell us about class, power and sex? It may surprise many to hear that high heels were first worn by men.(Image: Photograph taken of a woman in heels by Maria Pavlova - Getty)

Solitude - time on our own – has had a bad press. It’s certainly becoming more common in many parts of the globe, as seen in the increasing numbers choosing to live alone. But it’s easily confused with loneliness, or demonised as weird or threatening in the form of ‘the loner’. So how far can or should we pursue solitude? How does it relate to our hyper-connected world? We hear from a ‘semi-hermit’ on how she lives her life, a survivor of solitary confinement who also feared compulsory company, a champion of ‘the loner’s manifesto’ and an expert on global solo living.(Image: A lonely man watches the sun-rise as he sits on top of a mountain. Credit: AFP/Getty Images)

Secrets have become harder to conceal and easier to divulge with the availability of online blogs and other social networks sites as well as open office settings. Secrets can be used as weapons. They represent power, they can generate fear. In the shadowy world of espionage and in our ordinary lives secrets are a currency. But why do we have secrets? And what are the consequences either for holding onto a secret or for giving it away?(Image of a woman holding a finger to her mouth. Credit Getty Images)

Dr Michael Mosley, a self-proclaimed 'proud pessimist', says that given a choice he would prefer to be an optimist, as pessimism affects his relationships and optimists tend to live longer. So he recently agreed to try and convert his darker outlook on life to a brighter one. Over seven weeks, his brain was manipulated by psychologists at Oxford University for a BBC documentary in order to try to turn Dr Mosley into an optimist. He reports back on the success or otherwise of the experiment. But do we have a choice? Ros Taylor says we do. Once a pessimistic average opera singer, she realised that her real passion in life was psychology. She retrained to become a clinical psychologist and claims to have taught herself to become a 'pragmatic optimist'. Mike Williams puts optimist Ros Taylor up against pessimist Michael Mosley to ask if the glass should be half-full or half-empty and why should we care?(Image: A glass of water on a wooden table. Credit: Getty Images)

We all do it… don’t we? If your answer is no perhaps you’re doing it right now. Many psychologists argue that learning to lie is an important stage for children. As early as two, children who are more developmentally advanced are much better liars. For some people, lying is something they can’t stop doing. We hear from someone whose life spiralled out of control due to her addiction to lying. But is every lie bad? The concept of a ‘white lie’ is one we teach our children from an early age but different societies socialise their children to tell different sorts of lies. East Asian societies might be more aware of a ‘blue lie’ for example.Mike Williams explore how different cultures define telling the truth and what that shows us about our societies.(Image of a hand held on top of a bible.Credit: AFP/Getty Images)

The Manifesto of Futurism written in 1909 declared that “the splendour of the world has been enriched by a new beauty: the beauty of speed!” And the addiction has taken hold. So what is it about speed? A desire to lose control, a suppressed childishness or just the reality of 21st Century urban life? And what would the speed merchants of 1909 in their 190 km per hour roadsters make of today’s rocket propelled cars trying to reach 1600 km per hour? Mike Williams meets the students of the Bloodhound club at Heathland School west London, Wing Commander Andy Green preparing himself to attempt a new land speed record in Bloodhound SSC and experiences a bit of speed for himself on the Mercedes Benz World test track.(Image: RDC 500 mile motor race at Brooklands race track in Weybridge, Surrey 1929. Credit: Getty Images)

Why do humans bully, why do some do it and others allow it? Are bullies born or do they learn their bullying? Mike Williams speaks to anthropologist Christopher Boehm about links between the bullying behaviour of our ape ancestors and our own behaviour. He also speaks to author Helene Guldberg about the challenges defining the term as well as performance poet Shane Koyczan about his experience being both bullied and being a bully.(Image of a teenage boy bullying another boy. BBC Copyright/Corbis Royalty Free)

#*?@! %$&@*! Why do a few, select words have such power to shock and offend? With help from swearing historian Melissa Mohr, Mike Williams traces the history of taboo language from Roman times to the present day and hears how cultural taboos have shaped offensive language down the centuries. He talks to American psychologist Professor Tim Jay about why we swear and discovers that children start using profane language at a much earlier age than you might imagine. And he meets psychologist Dr Richard Stephens who persuades him to take part in two swearing experiments, one of them rather painful, with some surprising results.(Picture: A teenage boy in a hoodie making an offensive gesture, censored. Credit: BBC)

Burial is a practice that’s been carried out for centuries by different cultures and religions around the world – but why do we do it? Mike Williams goes to a Jewish cemetery where Mitzi Kalinsky from the Jewish Joint Burial Society explains the reasons behind their burial practices. He talks to Caitlin Doughty, an American mortician who is trying to revolutionise burial practices in the US and considers what he would like to happen to his body, after he dies.(Image: Gravestones in a cemetery. BBC copyright)

Why do we look back and yearn for the past, longing for some golden age when society was supposedly simple, innocent and kind? Why do we recall sweet memories of our youth? And the bitter-sweet memories of love and loss?Mike Williams speaks to a social psychologist who reveals that looking to the past can protect us in a number of surprising ways. He hears from a woman from the former German Democratic Republic who waxes nostalgic about life there. And he meets a man born in the 1970s who spends most of his time living in the 1940s.(Image of holiday makers waving at the seaside in 1930. Credit: Getty Images)

Helena Merriman asks why people listen to sad music. A recent study has shown that sad music has become increasingly popular, but why do people choose to listen to it, and what goes on in the brain and the body when they do so? Helena speaks to Japanese pianist and music researcher Dr Ai Kawakami who has some surprising answers about some of the positive feelings people experience when they listen to sad music. American writer Amanda Stern tells Helena why she regularly listens (and cries) to sad music and British composer Debbie Wiseman, known for her moving TV and film scores, explains what makes a piece of music sound sad. You’ll also hear pieces of sad music suggested by BBC listeners from all over the world. (Photo: A woman with headphones on, listening to sad music. BBC Copyright)

Humans need to eat to survive. So why would someone go voluntarily without food - or even water? Many of the major religions observe periods of fasting for spiritual reasons. Charlotte McDonald speaks to those who have fasted to find out why they do it. Also, is there a place in modern society for fasting for non-religious reasons? She speaks to Michael Mosley about the science behind fasting and why some people are choosing it as a lifestyle choice.(Image: Indian Muslims offer prayers prior to breaking their fast on the first day of the holy fasting month of Ramadan. Credit: AFP/Getty Images)

Memory plays a big part in shaping our identity, but can we rely on what we recall about ourselves and about others? Mike Williams finds out how human memory works and why some memories flood back more easily than others. He also explores whether different senses trigger different types of memories. Mike speaks to memory experts Martin Conway, Elizabeth Loftus, Gisli Gudjonsson, Maria Larsson and Simon Chu. The reader is Roberto Pistolesi.(Photo: Image of a brain scan. Credit: AFP/Getty Images)

Why do so many women feel the need to get rid of their body hair? Why is it fine for a man to sport hairy legs, but unthinkable for most women? It’s a sensitive subject - touching on ideas about female sexuality and gender politics that stretch back almost to the beginning of time.(Image of an actress with her arms up in the air, posing for a portrait. Credit: Getty Images)

Around the world people have different rules for their relationships - rules often dictated by culture and religion. In many societies the most important of these is sexual fidelity - true love and monogamy are expected to go hand in hand - but why should love mean forsaking all others? And what happens to relationships when monogamy is cast adrift?(Image of couples kissing and celebrating the eve of Valentine's Day. Credit: Getty Images)

Why has the modern world become so obsessed with celebrity culture? Where does it come from? How do you achieve it? And how do you fake it? Mike Williams hears from Brett Cohen, a man who fabricated his own fame and became famous for not being famous. He also speaks to an academic who argues that evolution has left us foolishly following unsuitable celebrity role models. From the world's first celebrity to the pop-icons of today, why are they adored by millions and why are they so influential? It is easy to understand why you might want to buy football boots endorsed by David Beckham, but why would you want underwear which carries his name? Or a perfume endorsed by singer Beyonce. Or George Clooney's favourite coffee?(Image: Justin Bieber arriving at a music video awards ceremony in Toronto, Canada. Credit: Getty Images)

For the last few hundred years, humans have tried to scale ever more dangerous peaks. But why do they do it? Mike Williams travels to the Alps to find out. He speaks to skilled climbers including the son of American mountaineer John Harlin II, who died trying to scale the north face of the savage Eiger in Switzerland. Why do they take such risks and what do they get out of it?(Image: North Face of the Eiger Mountain in the Swiss Alps. BBC Copyright)

***Warning: This programme contains graphic descriptions of violence*** Why are we so drawn to violent entertainment? Violent films, video games and stories are very popular, as were brutal gladiatorial Roman contests and gory 14th Century jousts. What explains this enduring attraction to violence? Helena Merriman talks to the Mexican director of Heli, a professor of fairy tales and joins one of London’s most gruesome serial killer tours to answer this week’s question.(Image of Daniel Craig pointing a gun, as James Bond. Credit: Eon productions via Press Association)

Why are attitudes towards older people often so negative? Traditional definitions used to mark old age at around retirement - 60– 65 years. But with many of us expected to live well into our 80s and beyond, that now seems absurd. Mike Williams talks to the old and the young, and asks how might we re-think of this period of our lives ? (Image: A woman holds the hands of an elderly relative. Credit: AFP/Getty Images )

In this programme, Mike Williams asks why people have tattoos. Where do they come from and what do they say about us? From the Maori of New Zealand to the Mexican Mafia, Mike explores the universal motivation behind why people decorate their bodies with ink. (Image: David Beckham's tattooed bare back. Credit: AFP/Getty Images)

Why do we have such a fascination with fire? Our attempts to master fire have shaped who we have become – in some cases civilising us, but in other cases, corrupting us. What motivates arsonists to use fire as a weapon and what do the various myths about the origins of fire tell us about how we view its power?(Image: A boy practising fire breathing on the roof of a building. Credit: Getty Images)

These days we humans have become an urban-dwelling species. So how has the city changed us? What are the pros and cons of life in a modern metropolis? From the experience of a single individual we'll zoom out, to view neighbourhoods and communities and to the city as a whole - a place that we have shaped and which, in turn, shapes us.(Image: Commuters drive past the city of Bangalore. Credit: AFP/Getty Images)

Why do we bathe? The second of two programmes examining the rituals of bathing. Last week: spiritual purification and supernatural waters. Do you enjoy a hot bath or is water too precious where you live to bathe in? This week is about cleansing the body and clearing the mind… water, health and well-being. All of our programmes are available by clicking on the Free Downloads services. (Image: A Japanese woman takes a bath in a natural hot spring, in Nagano Prefecture, Japan. Credit: Getty Images)

Why can the seemingly everyday activity of bathing mean so many different things for millions of people around the world? For some, unwinding in a nice, hot, soothing bath is a just reward after a long day’s work. For others, it’s an imperative act of religious faith. In the first of two programmes on bathing, Mike Williams asks: Why do we bathe for purification? He looks at the rituals and symbolism of bathing: to wash away our sins, cleanse our souls, to prepare ourselves for an encounter with the divine. From ceremonies of purification of the Christian baptism to the Sacred River Ganges, from the ancient Roman Empire to the modern Middle East, he traces the history of ideas associated with healing, spiritualism, purification and re-birth through the act of bathing.(Image: Hindu devotees bathe in the waters of the holy Ganges river believed to be the largest religious gathering on earth. Copyright: Getty Images)

Why is that so many of us are drawn to the ocean... to the sound of tumbling waves and the sights and smells of the sea?It captivated the likes of Melville, Shakespeare and Byron. Whether to view it from the shore, out on the waves, or under the surface, people flock to the ocean. Mike Williams explores literature and science to discover what it is about the sea that is so compelling. He speaks to Hanli Prinsloo, a free-diver, from Cape Town in South Africa.(Image: Two men walk into the sea, under a sunny sky. Credit: AFP/Getty Images)

It is an essential part of women’s days all around the world – putting on their face before they leave the house. This week Mike Williams explores why millions of women and some men paint their faces.The programme delves back into history to look at why it was worn in the past and how this has shaped what we do today. He looks at the rise of the makeup industry and how it has struggled to overcome cultural and biological boundaries particularly when trying to sell to men. He asks whether the sheer scale of the make-up industry is driven by marketing or if there are more, innate biological reasons for the practice – a desire to look attractive and powerful.(Image: A man applying mascara to his eyelashes. Credit: AFP/Getty Images)

A ball is a simple, everyday object that holds such a deep appeal for us. We have been playing with them since the dawn of time on every continent. Mike Williams finds out why. Some scientists argue that ball playing helped us become human, by developing the parts of the brain involved in speech, emotions and decision making. But why is ball playing fun? One explanation is that the unpredictability of never quite knowing where a ball will fall gives us the kinds of emotional highs and lows that would take unusually good fortune, or tragedy, to get otherwise. (Image: a young boy holding a ball. Credit: AFP/Getty Images)

Many psychologists argue that learning to lie is an important stage for children. As early as two, children who are more developmentally advanced are much better liars. For some people, lying is something they can’t stop doing. We hear from someone whose life spiralled out of control due to her addiction to lying. But is every lie bad? The concept of a ‘white lie’ is one we teach our children from an early age but different societies socialise their children to tell different sorts of lies. East Asian societies might be more aware of a ‘blue lie’ for example.We explore how different cultures define telling the truth and what that shows us about our societies.(Image: Woman holding her hand on the bible. Credit: AFP/Getty Images)

Disgust is something that we all experience, but what purpose does it serve? And what role does it play in our moral judgements?Mike Williams speaks to the ‘disgustologist’ Val Curtis about how revulsion protects us from disease and learns how disgust can be used – and abused - as a political weapon. He tests the limits of his own disgust, finds out what it’s like to be the object of someone else’s disgust and explores the idea that there is “wisdom in repugnance” with philosopher Steve Clarke. (Image of actor and comedian Frankie Howerd tasting his own cooking at home. Credit: Getty Images)

Why do we live with cats and dogs? Mike Williams meets cat and dog owners in Kenya and North Wales to find out what the real nature of the relationship with our furry friends is. Where did they come from? Why do we become so attached to non-humans? Can they love us back? Mike talks to psychologist Sam Gosling who has studied whether there really are cat and dog people. And he questions whether the relationship is really all about fluffy cuteness – could there be a dark side to our keeping of pets? Human geographer Yi Fu Tuan thinks so.Produced by Lucy Proctor.(Image of an owner kissing her pet cat. Credit AFP/Getty Images)

Gold - what is it about this rare, inert metal which has captivated us for thousands of years? The answers may not be what you might think. Mike Williams explores our obsession with gold. He looks at chemistry, Einstein's theory of relativity and the many myths and mystery of glorious gold.(Image of gold bars. Credit AFP/Getty Images)

It’s something that all individuals and societies have done for millions of years. But why do we sing? Today singing is a way of bringing people together, expressing joy, sadness and almost every emotion. Is there an evolutionary reason why and how humans developed the complex vocal structures involved in singing? Mike Williams talks to biologists, voice coaches and vocalists to find out.(Image of Chinese women singing in a choir in Chongqing, China. Credit Getty Images)

Why do humans kiss? You might think it is a universal trait, something that we all do. But when European explorers travelled the world, they met tribes that didn’t kiss. So is it a learnt response after all? ? It can be as a greeting, or a sign of reverence or supplication - but we will be talking about the romantic kiss - face to face, lips to lips. We examine the biochemistry, psychology, anthropology and history of kissing. Where does it come from? (Image of two women kissing at a festival, credit AFP/Getty Images)

Why are attitudes towards older people often so negative? Traditional definitions used to mark old age at around retirement, 60–65 but with many of us expected to live well into our eighties and beyond, that now seems absurd. Mike Williams talks to the old and the young, and asks how might we re-think of this period of our lives?(Image of a woman holding hands with a relative. Credit: AFP/Getty Images )

The idea of retirement is historically new. But with widespread demographic changes now meaning that many of us are expected to live into our eighties and beyond, how much sense does it make to stop people working when they reach their mid-sixties? Mike Williams looks at retirement asks how we might re-think this period of our lives.(Image of a carpenter working in his workshop. Credit AFP/Getty Images)

Around 10% of the global population suffers from insomnia. Contrary to popular belief, it is not more prevalent in bustling, noisy cities nor in workaholics. While we might think of insomnia as a modern malaise, people have always had trouble sleeping but are some of us more susceptible to it than others? If so, why? Where did the idea that we all need seven or eight hours sleep come from? Is it true? Can insomnia really affect our genes and shorten our lives? What really works to cure it? The experts tell us what they think works and why. And we hear from insomniacs around the world about their search for a good night’s sleep.

The first of two programmes which looks at human behaviour and sleep Why do we Sleep? At first glance, it seems a silly question but actually it is one that’s been baffling scientists for decades. We spend a third of our lives asleep, but sleep science hasn’t got much further than being sure that we sleep because we get sleepy. As Mike falls into a deep slumber to the sound of his own recording voice, we will find out exactly what happens when we sleep, from circadian clocks to sleep spindles to the famous REM, and how we have thought about this dark and private side of our lives across ages and cultures. We explore conflicting theories about the purpose of sleep. One theory is that we developed our sleep patterns to allow our body and mind to repair itself at night. While we know our body grows and heals while we sleep, we know much less about what our brain is doing and a century after Freud and Jung’s explanations, we’re still far from scientific consensus on what dreams are for. Are we consolidating memories? Are we rehearsing our responses to threatening situations? Or is it all random imagery created by an organ that is designed to be awake and can never fully shut down? Another theory is that while our bodies use the opportunity while we are asleep for restoration, it is not why we evolved to sleep around eight hours a day. Could it be as simple as we sleep because our ancestors didn’t need to be awake any longer?(Photo of actress Joan Gardner asleep in November 1933. Credit: Getty Images)

What role does silence play in our increasingly noisy lives? Why can silences be so poignant or so awkward? Strangely for radio, the programme will contain lots of silence… and the thoughts of musicians, scientists, religious thinkers and others.(Image: The inside of the anechoic chamber room, one of the quietest rooms on earth. Credit: BBC Copyright)

This week we’ll explore Post Traumatic Stress Disorder - PTSD. What is it? And why is it so controversial? Many people in the world are exposed to extraordinary, traumatic events- wars, earthquakes, accidents and crime. Most recover in time but, for some, the trauma takes over their lives, leaving them unable to function. Mike Williams talks to a war veteran and a tsunami survivor, who tell their stories of how they came to be diagnosed with PTSD. But do the public know what this diagnosis really is? Or has it been confused with a broader term for anyone who has suffered a trauma? Is it a useful diagnosis across cultures?(Image of French soldiers in vietnam. Credit:STAFF/AFP/Getty Images)

We all have memories but do we share some of those, socially or collectively? If so, why? Most countries have things in the past which they’d rather forget but how successful or otherwise are elites at coercing our “collective” memories or manipulating national narratives? Mike Williams looks at the concept of cultural and collective memory and asks if after wars, or a period of intense trauma, is it best to confront our memories or is a period of silence the best way to come to terms with the realities of the past?(Image of Vorochilov, Molotov, Stalin posing at the shore of the the Moscow - Volga Canal in 1937 in this manipulated picture. In the original picture Nikolai Yezhov was standing on the right. Yezhov was the senior figure in the NKVD (the Soviet secret police) under Joseph Stalin during the period of the Great Purge. After Yezhov was tried and executed his likeness was removed from this image between 1939-1991. Credit: AFP/Getty Images)

Millions of us work in open plan offices, whether in modern, efficient buildings with the latest technology and design, or in more traditional set-ups with rows and rows of desks. Mike Williams asks why the open plan office has become the norm in many places, and whether they are as good for the workers, as for the bosses’ bottom lines. Open plan offices have many advantages: a higher density of people means big savings in real estate costs. They also make it easier to communicate, help or seek help from co-workers. They even make your boss seem more accessible. But the downsides are considerable. People find they get distracted by co-workers’ phone calls and conversations and scientists report that this impacts on your concentration and productivity.(Photo: Image of workers in an open plan office. Credit: BBC)

From the mythology of night time and darkness, to being rebellious and cool, to a word which has come to define a race of people, black, as a colour and a concept, has always meant many things. Why? Where do positive and negative ideas that have been associated with black come from, how much resonance do they still hold today? Mike Williams peers into the world of black, its science, history, psychology and politics and asks why black has so many different meanings.(Image of black and white grid, BBC Copyright)

Why do we behave differently in crowds? An “angry” mob and “herd mentality,” – are terms frequently used to describe events like the London Riots of 2011. But is there really something in us that changes when we are in a large crowd? The French 19th Century psychologist Le Bon, believed that in a crowd we lose our minds, our sense of self and with it our moral compass. If he’s right, can we really be responsible for our actions when we are in a crowd? And should this be taken into consideration in criminal trials? Or do large crowds have their own social identity, an identity which can be peaceful or violent. Some social psychologists think the difference between an angry mob and a peaceful crowd often depends on how that crowd is treated by the authorities. Are they right? Or is the morphing of a crowd into a mob a completely random phenomena? (Image: A general view of a crowd in the Mall, credit Oli Scarff/AFP/Getty Images)

Each day billions of us look into a mirror without giving it a second thought but do we really understand what we’re seeing?This week, Mike Williams explores the science and history behind the mirror and hears about the myths and mysteries of this everyday object.(Image of customers seen in a mirror as they shop for goods. AFP PHOTO. Credit to Louisa Gouliamaki - Getty Images)

Why has the tiny area of Bukom in Accra, produced five World Champion boxers, including Ghana’s greatest ever fighter, ‘The Professor’ Azumah Nelson? What does this area tell us about raw talent versus environment in the nature/nuture debate? Why are the men of Bukom so good at boxing? Find out with Mike Williams on the Why Factor.(Image of Azumah Nelson trading blows during a bout in Las Vegas, Nevada. Getty)

Why do tens of millions of women all over the world choose to walk around on stilt like objects called heels? Where did the fascination with elevated footwear come from and what do they tell us about class, power and sex? It may surprise many to hear that high heels were first worn by….men.(Image: Photograph taken of a lady in heels by Maria Pavlova - Getty)

Why has one of the world’s most important scientists been forgotten? He worked with something without which, we'd all be dead. It's in our DNA and the plants we eat could not exist without it. Fritz Haber was the brilliant German, Jewish chemist who used nitrogen to help feed billions but also used science to prolong the First World War where tens of thousands met a dreadful end. With Mike Williams.(Image: Fritz Haber Photo by Topical Press Agency/Getty Images)

On the programme today, the strange customs and conduct that make up ‘good manners’. Where do they come from? What purpose do they serve? And how do they change from place to place?...We’ll serve up linguistics, civility, civilisation and some gender politics too.(Image of English film actor Roger Moore opening the door of his Volvo for Isabelle McMillan in a scene from the television series 'The Saint' Credit: Getty Images)

Sinister tales of characters that terrorise adults and children at night pervade our cultures and have been handed down from generation to generation over the centuries, be that Kenya’s Nightrunners with their supernatural powers or the European Sackman – the monster or man, who takes away naughty children in a sack. In Iceland and the Netherlands this Child Catcher comes at Christmas, an altogether different version of the American Santa Claus. Why do we tell each other these stories? And what happens when folklore meets the modern world?(Image of girl having nightmare Credit: Maria Pavlova, Getty)

Why are human beings compelled to tap their feet or bob their heads to the beat of music? It seems like a very basic thing to do. But no other animal is able to synchronise their whole body to a beat in the way we do, and very few other animals can even recognise a beat. Mike Williams goes in search of where exactly in our bodies we feel this beat and what evolutionary purpose the ability to drum and move to the drum beat might have had.(Image of a man playing drums - credit: Getty)

This week the second of two programmes about fear, why do some of us like to be frightened? Why, in a darkened cinema, do we enjoy and endure fear, horror and suspense? We'll delve into the human mind to find out. We will also go behind the camera to learn how the film-makers manipulate our senses and play on our deepest, most primeval fears.(Image of Janet Leigh Credit: Associated Press)

In the first of two programmes on fear, we ask what actually fear is and discover it's a surprisingly difficult question to answer. What does fear mean to us and how do we face our fears, imaginary or otherwise? Are our fears universal or culturally specific?*Image of Fear - Credit Getty Images*

This is the story of what happens when running water comes to town. In a rural backwater in southern Ghana the instillation of a network of standpipes six years ago made life feel more safe and secure. But very soon land prices shot up and the rich began to move in, connecting their own private taps to the water system and draining the reservoir. The simple addition of taps has changed this region forever – but what does it mean for the everyday lives of the people that live there?

In the physical, material sense, it's quite rare in nature... But, at the same time, it surrounds us. Babies can't detect it. The Himba tribe of Namibia can't describe it. Pablo Picasso turned to it after a friend committed suicide and in the West it's creative and reliable in the East it's cold and deathly. This week on the Why Factor, we're talking about something different - the colour blue.

Why do different cultures have different coming of ages? For some the advent of adulthood is celebrated by lavish parties, for others, by endurance tests and initiation ceremonies. But they all share a commonality - the symbolic passing of childhood into the adult world which usually confers new rights: legal, political or religious. But what really changes? And why is adolescence, for many, lasting longer than ever?(Image: Mexican teenagers pose for photos following quinceanera, a coming of age party. Credit: John Moore/Getty Images)

This week, Mike Williams asks why do we shake hands? All over the world millions of us use this gesture to greet others but where does this everyday ritual come from, and what purpose does it serve? With the US presidential election just days away, Mike also looks at the role of the handshake in political life - why has it proved to be such a sensitive issue?(Image: US President Barack Obama (R) and Republican presidential candidate Mitt Romney (L) shaking hands. Credit: TIMOTHY A. CLARY/AFP/Getty Images)

Why do we care so much about the hair on our heads? Each year we spend billions of dollars on cutting, shaping and colouring our hair. It's important for personal reasons, cultural and symbolic reasons too. But why? Find out, as we hear the stories of people who have had their hair taken from them. Join Mike Williams for The Why Factor.(Image: A US soldier getting his head shaved. Credit: JOHANNES EISELE/AFP/Getty Images)

At first glance, it seems like a very obvious basic human response - we laugh because we find things amusing. But what is it that actually triggers our laughter, do all of us find the same things funny? In the edition of The Why Factor, we also look beyond comedy, at laughter in our everyday lives and the role it plays in the relationships between men and women. We also hear some surprising and disturbing discoveries. Why, for instance, were those who carried out the massacre at Columbine laughing as they shot dead 13 people?(Image: Comedian Omid Djalali. Photo by Thos Robinson/Getty Images)

Mike Williams finds out why armies use one type of bullet, while gangsters use another and what the phrase full-metal jacket tells us about our qualms about killing each other. The bullet has been at the heart of the world's battles for many centuries. Although the essential idea hasn't changed much since the 15th Century, the way the bullet and its use has evolved is revealing. He hears from doctors, soldiers and criminals about why such a small object causes so much damage and what it means to shoot someone, and be shot.

In this week's programme Mike Williams looks at why people start smoking. Nearly 50 years after the world first learned that smoking kills, millions are still picking up the habit. He also discovers who was behind one of the most lethal inventions of all time - the cigarette.(Image: The silhouette of a woman as she smokes. Credit: Danny Lawson/PA Wire)

This week, the lift - millions of us use this piece of machinery every day but barely give it a second thought. But the lift, or elevator, is an intriguing place where strange things seem to happen to us. In today's programme, Mike Williams looks at the history of the lift, why we seem to behave so oddly inside them and why Hollywood has made the lift such a scene of disaster.(Image: A person walks past the 'Untitled' installation of miniature elevators by Maurizio Cattelan. Photo by Mario Tama/Getty Images)

Why do we do the things we do? Mike Williams searches for the extraordinary and hidden histories behind everyday objects and actions. This week he looks at the paradox at the heart of the human condition - the desire to belong and to conform, but also to hold tight to our individuality. And we see a symbol of this paradox everyday in an apparently useless piece of clothing about 150 centimetres long - the necktie. Why do we wear ties?(Image: Former astronaut Buzz Aldrin wearing a tie with space designs. Credit: REUTERS/Evan Vucci/Pool)

Why do we do the things we do? Mike Williams searches for the extraordinary and hidden histories behind everyday objects and actions. So much of what we do is assumed, it seems almost second nature. But where do those ideas, decisions and behaviours actually come from? The series sets its own agenda and draws upon many but interconnected approaches: psychological, cultural, historical social anthropological, philosophical. It informs us about about the way we live now, about the human condition in the 21st Century. In this first programme, Mike asks why people have tattoos.Where do they come from and what do they say about us? From the Maori of New Zealand to the Mexican Mafia, Mike explores the universal motivation behind why people decorate their bodies with ink. Broadcast and podcast every Friday from September 2012.(Image: David Beckham's tattooed bare back. Credit:ORLANDO SIERRA/AFP/Getty Images)