The Why Factor

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 KnightImage 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)

Scientist Nikolaus Steinbeis discusses the brain region activated during sharing and children's struggles with sharing. Topics include the distinctions between sharing and giving, challenges faced in competitive settings, life in a communal household, sharing behaviors in different age groups, and the importance of sharing in software development and community building.

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)