In 1956, the science fiction writer Isaac Asimov published a short story called Jokester. Set in a future where human affairs are run by a giant computer called Multivac, it concerns a Grand Master, a member of the elite whose role is to communicate with the great brain.

One day, the Grand Master is overheard telling a joke to Multivac. What is he up to? Has the pressure of work got to him? When challenged, the Grand Master explains that he has asked Multivac to tell him where jokes come from. “I never met anyone who ever claimed to have constructed a joke,” he says. “It’s always ‘I heard a good one the other day.’ ” The answer, when it comes, is alarming. Jokes, says Multivac, are being fed to the human race by an extra-terrestrial intelligence as part of a vast psychological experiment. And even more alarming is the certainty that, now the aliens have been rumbled, they will begin a new experiment of an, as yet, unimaginable nature.

Psychologist Richard Wiseman and his team of researchers at the University of Hertfordshire are expecting rather less dramatic results from their year-long Laugh Lab project, set up in conjunction with the British Association for the Advancement of Science as part of the Government-sponsored Science Year (www.scienceyear.com). Yet they have much in common with Asimov’s joke-telling hero. For they too are using jokes as a way into that most baffling of all subjects - the nature of humour.

Using the internet, a resource undreamed of in 1956, they are inviting people in 70 countries to feed their favourite jokes into a central database. Senders will also be asked to register their reaction to selected jokes, and to supply information about themselves. “Rather than going in with hypotheses, we are going to look at what the data might be trying to tell us,” says Dr Wiseman. “You can do that when you have such a vast amount of it, which is why this feels like such an unusual experiment to be doing.”

As the responses come in, it should be possible for the first time to draw important inferences about humour, such as whether men and women laugh at the same things and whether people from different countries have different senses of humour. And when the team begins to analyse the accumulated data in September, they might well have the means of clearing up an even deeper mystery. For questions such as: “What makes some things seem funny?” “Why do we laugh?” and “What is the function of humour?” seem to lie at the heart of what it is to be human - which may be why they have taxed our greatest thinkers since earliest times. Satire, in which the shortcomings, follies and vices Continued over page of people and institutions are censured through irony, burlesque or straightforward ridicule, was already a finely honed tool by Roman times. According to Aristotle, it began as a form of magic, in which utterances were hurled at individuals to drive out evil.

However, both Aristotle and Cicero reckoned that the most frequent causes of laughter in classical times were ugliness and deformity, and 2,000 years later, Francis Bacon agreed. Even during the renaissance, aristocrats collected dwarfs and hunchbacks for a giggle. Descartes considered laughter a manifestation of joy mixed with surprise or hatred, and in his Leviathan of 1651, Thomas Hobbes wrote: “The passion of laughter is nothing else but sudden glory arising from a sudden conception of some eminency in ourselves by comparison with the infirmity of others, or with our own formerly.”

Some early experimental psychologists also saw feelings of superiority as the cause of laughter. But it was the philosopher Immanuel Kant who came up with the idea that a sudden release of tension might be at the heart of it. Herbert Spencer, the 19th-century English philosopher, went further, suggesting that a “liberated nerve force” might give rise to involuntary bodily movements, and Freud took a similar line, calling the nerve force “psychic energy”, and tracing the smile back to the satisfied smirk of a well-fed baby.

When we laugh spontaneously, 15 facial muscles contract and our breathing pattern changes. Spontaneous laughter is a motor reflex, common to all humans regardless of culture (unlike kissing, for instance, which is unknown in some cultures). But while we are all wired to perform this feat, most of us also learn to laugh consciously (when the boss makes a joke) and to suppress or modify our laughter (when the boss is angry).

Scientists have measured the electrical currents involved in smiling and watched the voltage rise as the smile becomes a fit of loud guffaws. Some claim to have got similar results by tickling rats, and work with a variety of mammals has suggested that laughter in some form or other is common to many species and is likely to predate language as a means of communication.

But if laughter is just some primitive physiological reflex that humans have tailored to suit social needs, what of humour, the highly complex psychological stimulus that provokes it? When primates are taught American Sign Language, they invariably show signs of a crude sense of humour (“Put the banana in your mouth,” one researcher urged a chimp who wasn’t eating. “Stick the banana up your nose,” came the reply.) And which of us has not been convinced at some time that the family pet is having a joke at our expense? But humour that is more than teasing or slapstick - humour that relies on language and subtle cultural references - is clearly one of the defining human traits. Even quite sophisticated artificial intelligence systems have so far been able to do little more than feign it.

So what is its purpose, and what evolutionary advantage might it once have conferred on our primitive forebears? On this point at least, a definitive answer is in sight.

Already, scientists at the University of Rochester School of Medicine in the US have used functional magnetic resonance imaging to identify the area of the brain most active when we find something funny (for the record, it’s the ventromedial front lobe). Further research into how humour is processed and what other mental functions it is related to should eventually tell us how and why it developed in the first place. But until then, much of our thinking comes down to pure supposition.

One explanation is that humour developed because it prevented quarrels getting out of hand. But as mollifying gags leave no fossil record, it’s hard to be sure that our conjectures about the past are not simply based on our own experience.

Dr Jason Rutter, a research fellow at Manchester University’s Centre for Research on Innovation and Competition, studies the social uses of humour, and he is sceptical about many of the traditional explanations. “The evolutionary theories tend to be strongly associated with superiority and aggression, and the idea that laughter is a sign of victory or relief after battle,” he says. “It is often said in evidence that the Eskimos had battles of humiliation where they would engage in joke telling rather than hand-to-hand fighting, but I never found a source for this story.”

Jason Rutter prefers the notion that humour is a means of defining in-groups and out-groups. “If I tell a racist or sexist joke and you laugh, you are showing agreement. In fact, a lot of humour is about defining micro-differences. We have very few jokes about the Japanese, considering the Second World War, but loads of jokes about the Scots and Irish,” he says. Most humour, of course, has nothing to do with formal joke-telling at all (“this man goes into a pub - stop me if you’ve heard it...”). He points out that, even in stand-up comedy, a fair amount of the laughing goes on before the comedian ever gets to the punchline, and the wittiest repartee is always a seamless flow of innuendo and word-play and never a sequence of jokes.

A New Zealand study of workplace humour shows it can perform a number of functions. It noticeably increases cohesion between workers (“workplaces where humour is encouraged are often happier,” says the report from the Victoria University of Wellington). But individuals may also use humour to defuse uncomfortable situations, or as a way of challenging their superiors while making light of it.

And in the same way as politicians and other public speakers consider it vital to pepper their rhetoric with jokes, managers often use humour to soften directives or criticism, making it harder for subordinates to question them. “It’s hard to laugh at somebody’s joke and then reject what they are saying,” says Jason Rutter. “And when some bosses come in and start joking with you, you know there’s trouble. It’s called management through laughter.” But if the various ways in which we use humour are self-explanatory, the same cannot be said of its content. Why do we find some word-play funny? Why are we almost reduced to tears by certain situations? Why do we find some musical phrases comical?

Once again, aggression, apprehension and malice - however faint - have frequently been cited as necessary ingredients in any humorous situation. A baby being tickled by its mother senses that it is under some sort of mock attack, and laughter, never far from tears, is a convenient safety valve for tension. It is said that anthropologists have observed African tribesmen reduced to hysterics by the convulsions of an injured animal, and few of us have not laughed at cartoons in which unthinkable injuries are inflicted.

While most educated adults, conscious of the pain they might cause, would now refrain from laughing at hunchbacks - indeed, would no longer find them amusing - theatre audiences of all ages still find pantomime dames hilarious, and the Ugly Sisters are as ugly as ever. It’s not hard to find fear and malice lurking amid the fun and frolics.

But where is the fear in a pun? It’s hard to swallow the explanation that a play on words puts us on edge because it makes an earnest conversation seem ridiculous. Aggression may be part of the story, but is it the principal common thread? “Humour is based on so many things,” says Jason Rutter. “But what most people come back to is incongruity. All of a sudden, something has two meanings at once. Some people say that incongruity is also aggressive, but what most people agree on is that, if you have a joke, there will be incongruity somewhere within it.” It’s their sense of incongruity - of things having two meanings at once - that partly explains why Jews are internationally renowned for their sense of humour, says Professor Christie Davies, of Reading University. Having analysed jokes from around the world, and published a number of books on humour theory, he has no hesitation in singling out the Jews as top comedians.

Partly, he says, this is just another aspect of their mental agility - a capacity to have fun with the world which derives, he believes, from their religious tradition. “But it is an awareness of always being in two worlds - of belonging in a Jewish world but, unless they live in Israel, of also living in someone else’s world. It’s two meanings - seeing both sides of a question, and always having to ask the question: Who am I?”

It is easy to identify incongruity in most forms of humour, from the practical joke which violently propels its victim into an unexpected situation, to the absurd Monty Python sketch which juxtaposes a verbose customer with an inarticulate pet-shop owner. Human beings seem to delight in the creative mental activity necessitated by the sudden bringing together of two mutually incompatible frames of reference. In other words, they find a clash of incongruities funny.

Even the sick jokes that seem to emerge spontaneously within hours of a tragedy - the death of Lady Diana, for instance, or the attacks on the World Trade Centre - have a strong element of incongruity in them, says Christie Davies, and the idea that they are a coping mechanism is, he believes, based on a false analogy with people whose jobs really do bring them into close contact with horrifying events.

“You’re sitting at home in one set of circumstances, and suddenly, television intrudes with a set of images and somebody telling you how you ought to react and think,” he says. “There is a tendency, particularly among men, to resist this, and to see it as incongruous, particularly when the person sobbing and shouting is suddenly taken away and replaced with advertising jingles.” While telling such jokes may have a machismo element to it, no doubt fulfilling one or more of those infinitely subtle social functions to which humans harness their sense of humour, the content may be based on straightforward incongruity.

If Jews are the champions when it comes to bringing together mutually incompatible frames of reference, how do other groups fare? Christie Davies, who has studied more than 10,000 individual jokes, and whose latest book on the subject, The Mirth Of Nations (Transaction. UKdistributor: EDS. Tel: 0207 240 0856), puts the Iranians second in the world league, with the Scots in third place. And then there are the Germans. Much of German humour, he says, is tied up with a national fixation with faeces. Germans also tell deeply offensive jokes about the Holocaust and about Turkish migrant workers, says Chrisitie Davies, although he was surprised to discover that the former are also told in Israel.

As for the Japanese, although they have humour, they don’t have jokes. None at all. “This seems to be connected with their conversational practices, whereby everything is handled with a certain kind of etiquette and anything that looks like some kind of rough play in verbal terms isn’t permitted,” says Christie Davies.

And when it comes to what men and women find funny, the difference could be even more striking. Although Laugh Lab is not due to close its database until the autumn, Richard Wiseman was able to report “a huge difference between the sexes” just a few weeks after the experiment began. “Looking through the top 10 jokes for women so far,” he said, “you can see that they are completely different than men’s. There is an underlying aggression in men’s favourite jokes which isn’t there with women. The difference is absolutely massive.”

Perhaps, after telling his jokes to the giant computer, Asimov’s Grand Master should have asked not where the jokes came from but where men and women came from. For it must be that the closer we come to understanding humour, the closer we come to understanding ourselves. Funny that!

THE WAY THEY TELL ‘EM

IRANIAN

A Turk drives into Iran with a new Mercedes and is stopped by a bunch of Persians. They open the door and pull him out, saying: “Who do you think you are, driving a Mercedes in Iran, eh?” They draw a circle in the dirt, and tell the Turk he must remain standing inside the circle or they will beat him. Then the Persians begin smashing up his car. Ten minutes later, when they have reduced the Mercedes to a twisted wreck, they look back at him and see that he is giggling. “We just destroyed your $40,000 car,” they say. “Why are you laughing?” The Turk replies, “Because I stepped out of the circle three times and you didn’t see me!”

GERMAN

“What are you doing in the karate-class?”

“We shatter bricks with the side of our hand.”

“And what’s that good for?”

“When you’re assaulted, you can defend yourself.”

“That’s understood. But how many times will you ever be assaulted by a brick?”

JEWISH

A Jewish lady calls a newspaper: “I’d like to run an obituary.”

“How would you like it to read?”

“Irving Cohen died.”

“That’s it? Irving Cohen died?”

“That’s it.”

“But you could get four lines in the obit. It’s included in the price.”

“All right. Irving Cohen died... Cadillac for sale.”

SCOTTISH

Did you hear about the last wish of the henpecked husband of a houseproud Edinburgh wife? He asked to have his ashes scattered on the carpet.

THESE WILL MAKE YOU LAUGH...

How do you make a scientist’s brain light up?

Science is at last beginning to understand how the brain processes jokes. Scans carried out at the Institute of Neurology in London and York University, Toronto, have shown that jokes such as puns are deciphered in one region of the brain, while other types of joke are handled in a different region.

And when it comes to laughing at either kind, a central pathway - a section of shared “wiring” - comes into play. In an experiment, 14 volunteers were scanned while listening to a variety of so-called semantic jokes: “What do estate agents use for birth control? Their personalities” and puns “Why did the golfer wear two sets of pants? He got a hole in one”.

Areas of the brain known to be involved in the processing of language were active while the subjects processed semantic jokes, while areas involved in speech production lit up when the subjects deciphered puns. When it came to laughing at both kinds of joke, the scans showed activity in the medial prefrontal cortex, which controls reward-related behaviour. The finding could explain why some people lose their sense of humour after damage to a particular part of the brain.

Belly laugh

Anyone who wants a really good laugh should visit one of the 37 known “laughing clubs” in Bombay. The participants engage in deep, yoga-like breathing, before reaching for the sky and repeatedly uttering a loud “ho, ho, ha, ha!” After a while, this forced laughter becomes contagious, until the entire company is laughing uproariously.

It is claimed this laughing behaviour reduces stress. So-called “holy laughter” is also an important part of the Toronto Blessing, a Christian revivalist cult sweeping Canada. Participants collapse in uncontrollable laughter, which is said to be a sign of the Spirit of God. Missionaries visiting remote tribes have documented similar group laughing among non-Christians.

Killingly funny

Zeuxis, a Greek artist living in southern Italy in the 5th-4th centuries BCwas one of the most famous painters of his day, chiefly on account of the realism of his paintings. Although none of his works survives, many have come down to us through copies found in Roman villas. Yet it’s not for these that he is known today, but for the fact that he is said to have laughed himself to death after painting a portrait of an old woman.