Philip Hensher: Have you heard the one about the scientist and the jokes?

'The funniest thing about Dr Wiseman's scientific experiment is that he made the attempt at all'

In reality, of course, the funniest joke in the world is the one about the penguin who goes into a bar and says to the barman "My bruvver bin in?" and the barman says "Dunno, what's he look like?" You see, he's a penguin, and the barman – oh, forget it.

The single funniest thing about Dr Richard Wiseman's scientific experiment to establish the best joke in the world is that he made the attempt at all. Funded by the University of Hertfordshire, Dr Wiseman's experiment has attached electrodes to hundreds of volunteers. Their responses were recorded to a lady in horn-rimmed glasses, a white coat and a red nose saying very slowly "Faith and begorrah, because it is a Rushin' Ballet."

At the end of all this scrupulous observation, a number of popular successes were observed. The most popular joke across the board was the one about somebody stealing Sherlock Holmes's tent, but Dr Wiseman divided up the responses according to different cultural groups, and indicated the jokes which were found funniest by women, men, Norwegians and other nations. And so the long day wore on.

It must be admitted that there may be something in Dr Wiseman's research, since the only joke of his I laughed at was, indeed, the favourite joke of the English – the one about the man with a lettuce up his bottom. "I'm sorry to tell you," the doctor says, "that this may just be the tip of the iceberg." The rest – my goodness, what palls of misery the rest of the world must subsist under, to extract merriment from such stuff.

The prize, alas, goes to the German nation – I know, they do have a sense of humour, they really do, but they seem set on keeping it well hidden. Their favourite joke, apparently, goes like this: "In what particulars is television justly described as a medium?" Half an hour of discussion follows, and examination of what the immortal Kant might have had to say on the subject, before a conclusion is reached. "The reason is that it is comparable to a steak, which when it is medium may be said to be neither rare nor well done. QED."

Jokes aren't the same thing as comedy – the funniest people I know never tell jokes, and the most humourless are often the ones who can't stop. You'll never catch Victoria Wood or Paul Whitehouse telling a joke, and, mostly, when joke-telling breaks out like measles in the pub, it is more like an attempt to be sociable than to amuse. It's mainly a male thing, but it's noticeable that many determined women have made the effort to master some jokes as a way into pub society. There is something mildly dreary about them, and the way that one joke will set off another, and a third, and whole evenings can pass without anything much in the way of conversation.

Still, you wouldn't be without them, and one of the striking things about Dr Wiseman's tragically doomed research is that it does at least demonstrate that jokes are only funny when they're not universal. His fallacy is to think that the most universally popular joke could ever be the funniest one. The fewer people who get them, the funnier they seem – hence the appeal of jokes on taboo subjects like dead babies and cripples, which are funny to an audience who can imagine a crowd of teachers and nannies chorusing "That's not funny at all."

I remember with shame egging Mr Rodriguez, my partner in crime, to perform his party piece, a recitation of that great French surrealist poem "Art phallique, art phallique, art phallique en ouate" (phallic art in cotton wool, but you have to say it out loud). It went down very well, but much better when a pompous and rather tone-deaf Francophile suddenly said "I don't get it". Alone in the group, he didn't see what was funny, and successive poems in the same vein, up to and including "Un petit d'un petit s'etonne aux Halles" had the effect of reducing everyone to hysteria, while he obliging kept saying "I just don't think that's funny at all." Very silly and unkind.

Laughter isn't always sociable – some of the worst attacks of hilarity occur at things which nobody else thinks are funny at all, such as, in my case, programmes about sick donkeys presented by Rolf Harris. What it always is is anti-sociable. Even in a huge audience, full of people laughing uproariously, there is always the powerful idea of a much larger audience who wouldn't laugh at any of this at all. One of the funny things about the English joke about the lettuce is imagining all those Germans who just wouldn't get it.

And for that reason, there is an cardinal rule about telling jokes: don't laugh at them yourself. Nothing is more offputting than thewould-be wit who is convulsed by his own punchline, for the simple reason that the deliciousness is in the suggestion that the audience with a sense of humour and the audience that don't get it might just converge in the man who tells the joke.

Jokes aren't the same as comedy, and good comedy is rarely made up of telling jokes, but you still laugh at a good one. And that reminds me of the one about the chicken who goes into the library.

hensherp@dircon.co.uk