Why do we laugh when someone falls over?

A man is walking down the street gazing into space. He doesn’t notice an open manhole, and disappears into it. It's hard not to laugh at a silly scene like this - but why we find it so amusing is an interesting question.

The philosopher Henri Bergson argued that laughter helps to maintain the rules of society. We learn to laugh at careless or eccentric behaviour, and this makes people pay attention to the requirements of the world they live in, because nobody likes being laughed at. Laughter pushes us towards being normal.

What do you get if you cross a sheep with a kangaroo? A woolly jumper! Sigmund Freud believed that jokes give us relief from all the effort of thinking properly. As we grow up, Freud thought, we get weighed down by responsibility to respond to the world in an orderly fashion. Jokes give us a holiday from this responsibility by coming up with impossible, surreal, or negligent answers to questions.

When around 100 sixth formers from ten different state schools spend the day at the University of Cambridge next Tuesday, to take part in a Challenge Day, these are some of the questions and theories they will be discussing. They will be introduced to the topic of humour, and what it does for us, in a taster session based on undergraduate teaching given by Dr Raphael Lyne, Lecturer in English and Fellow of Murray Edwards College.

The Challenge Days, which are run several times a week during the autumn and spring terms, are aimed at academically-able students who might not think about applying to Cambridge. They come from schools and colleges that are (nearly all) below the national average point score at A-level and above the average Free School Meals rate.

As a Cambridge academic, Dr Lyne spends most of his time writing and teaching about Shakespeare. He is the author of scholarly books and articles about Shakespeare's plays and poems, but he thinks that the high point of his career so far may be the moment where he spontaneously laughed at an Elizabethan joke about someone wearing cuckold's horns.

The joke in question comes from Shakespeare’s The Merry Wives of Windsor, first published more than 400 years ago. Falstaff is planning to dress up as Herne the Hunter, and Mistress Quickly says 'I'll provide you a chain; and I'll do what I can to get you a pair of horns'. It is not altogether easy to laugh at this today, and Dr Lyne won't be expecting his audience to take to it immediately... but it gives them a chance to think about why jokes work and last, and why they sometimes don't.

He thinks there is a lot to learn from the ways people have always sought out stories with happy endings and opportunities for humour. So he thinks we should take Shakespeare's comedies as seriously as we take his tragedies, because understanding happiness is as crucial as understanding disaster. His plays give food for thought about what makes people lucky in life and love -- and whether it's luck at all.

Dr Lyne will be encouraging his teenage audience to put a universal human experience under an academic microscope. He will introduce them - via snippets of Shakespeare, a skip through comedy theory, a mention for Little Britain, and anecdotes about his own small children - to the idea that being at university can be all about looking deeply into the things that really interest you, whether it’s why the sun shines, why we fall in love, or what makes us laugh.

“We often undervalue comedy in comparison with tragedy, with the result that we miss chances to think about how and why good things happen to us”, he says. “I think literature, and the humanities in general, have a lot to tell us about happiness, which is of course quite a buzzword at the moment.”

“When I talk to teenagers about taking comedy seriously it’s often a surprise for them – I hope it’s a nice one – and they get quite fired up thinking about how something they do for fun could be studied at a deep level. Sometimes they're quite resistant to the idea that laughter trains us to be normal, but sometimes they go for it straight away. I don't think it spoils laughter and jokes to think about them carefully – quite the opposite.”

Drawing by Cambridge University researcher Alex Driver, winner of Young Cartoonist of the Year competition 2010.