Instructions for Modern Living, Barbican, London

"Have you ever noticed," asks Duncan Sarkies, "that in just about every children's story you've ever read there's a happy ending?" And have we never realised, he says, the coercive aspect of such injunctions as "Merry Christmas"?

Most people's responses, I think, would be "Yes, when I was about six" and "Oh, don't be silly," respectively. Yet Sarkies earnestly delivers this sort of material for 80 minutes, while his fellow New Zealander, Nic McGowan, whistles, plays an electronic keyboard and xylophone, and produces the sound of police sirens or a watery bloop-bloop. A screen behind them shows grainy, flickering images of a suburban house or a car moving through city streets. "It's a very racist situation over there," says one of the men about England. (Sarkies does all the voices, with little variety.) "We don't have that problem here in New Zealand – we all get on with each other, don't we?" We all know what's coming: in less than a minute, the two chaps are discussing the sexual attractiveness of non-white people and their propensities for violence.

Along with its banality, Instructions for Modern Living suffers from uncertainty of tone. At times, Sarkies seems to pity the lonely, confused pawns of an atomised society, exemplified by an astronaut suffering anxiety attacks or a host of a radio call-in show whose phones are silent. But, behind the words, one feels, Sarkies wants to smirk at the inarticulate and desperate.

That hostility rises to the surface in the most successful sketch, which chronicles the affair of a manager of a fast-food joint with an employee: "Would you like to work in the service industry?" "Don't eat too many cheeseburgers or I'll get a new girlfriend." "Don't cry in front of the customers – this is a Happy Burger." The anger gives this sequence a lot more energy than the films of seagulls, dolphins, and raindrops.

As well as being cosmic and condescending, Instructions goes in for what its creators would probably call absurdist humour. They periodically appear on screen, in black tie, accompanied by such captions as: "When Nic and Duncan need confidence, they use creamed corn." To judge by their bringing such barely adolescent stuff to London, they must have used a truckload.

Instructions for Modern Living ends tomorrow (020-7638 8891)