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)