Stage Struck: Laughing matters

A few years ago, in London's Comedy Store, the performers in an improv group met a heckler they couldn't deal with. Until then, the show had been going fantastically well; energy and inspiration pinged back and forth between performers and audience, everything seemed hysterical. But not to one exasperated punter. Finally he stood up in frustration and blurted out, "You're just . . . saying things! And people are . . . laughing?"

It shows what a fragile thing comedy in the theatre really is; it crumples under self-consciousness. We’re all supposed to know the secret of comedy – which, I should say about now, without labouring the point any further, is timing! – and everybody prides themselves on their GSOH. But not only is comedy a maddeningly inexact science, laughter itself is barely understood. Plato, Aristotle, Kant, Kierkegaard and Freud will all offer you different theories as to why a man slipping on a banana skin is funny (in summary: a sense of superiority, surprise and, somehow, sexual repression), but, like any joke, these explanations shrivel under a microscope. Yet, in the summer, theatres put their faith in gut-busters, luring people into dark auditoriums with the promise of a chuckle.

One reason that stage comedies can be dependable, even weaker ones, is that laughter is contagious. A famous, extreme example, in a school in Tanzania in 1962, began when three girls got a fit of the giggles that led to a village-wide epidemic lasting two years. If other people's laughter can be that infectious, you see why sitcoms put the stuff in cans. Theatre doesn't have such luxury and, less liquored than a comedy club, it's much more exposed. There's nothing more fake in theatre than a forced laugh and perhaps that's why Chekhov (who labelled his sorrowful dramas "comedies") and Beckett (who preferred the term "tragicomedy") tended to split the difference. Comedy easily flips into its opposite.

If someone in the audience genuinely starts laughing, though, chances are that others will join in. That's certainly the logic behind a revival of Michael Frayn's famously clever farce, Noises Off, at the Bord Gais Energy theatre next month, or Shakespeare's comedy The Taming of the Shrew at the Kilkenny Arts Festival in August. Both plays are funny, Frayn's often hilarious, but they're much more complicated than advertised.

The failing show-within-the- show in Noises Off could have sprung straight from an awful anxiety dream, while Shrew has long been troubling for its unrelenting misogyny. In theatre, we're usually expected to empathise with the suffering of characters, but these plays are only really funny when you don't. We reassure ourselves that it's all unreal anyway, and these holidays from responsibility might make us return to our lives with refreshed compassion. As the heckler knows, they're just saying things. And we're laughing.