It's political certainly, but is it correct?

INSTALLATION ARTS Relocating the Remains Royal College of Art, London; Fat Cow Tannery Gallery, London

W hat it feels like to be black and what it feels like to be fat: hands-on experiences offered by two installation artists in shows that opened at the Royal College of Art and at the Tannery Gallery (in Bermondsey Street, south London) this month.

Confronted by the interactive CD-Rom game Caught Like a Nigger in Cyberspace and with an electronic mouse as a trigger, you know you have to shoot the black man jigging about within the superimposed gunsights in order to enter the scenario. With an all-black gallery staff watching you, it can be embarrassing - whether you are white or black.

Cyberspace is one of three CD-Rom / video works by the 36-year-old black British artist, Keith Piper, curated at the RCA by the Institute of International Video Arts.

Much of the impact of this, his 15-year mid-career retrospective, Relocating the Remains, comes from his use of stunningly brilliant digital technology as a medium for issue-led art.

In his video collage, Unrecorded Histories, a big screen shows hands turning the pages of the log book of a slave ship as the plan of a deck cargo of slaves drifts eerily across the background and the good ship Jesus, the first slaver, sets sail for Africa. The viewer, hand to mouse, is ensconced at a polished mahogany office desk lit by a brass lamp, as the images swirl and blend within a decorative gilt frame - posh objects redolent of dominant white culture. There is a soundtrack of sad negro songs.

But to return to the "nigger" lost in cyberspace: if you shoot straight, you will be rewarded with "a welcome beneath the silicon sun for you and your family" (a young white mom, pop and baby zoom out, grinning) and an opportunity to apply for entry by choosing the user profile that best describes you. The correct (as in PC) click-on choice is either the nerdy Tech-Head or Other, a black silhouette. But the successful choice is the Al Gore Lookalike. It's witty.

"Others" are invited to abandon their application, to trespass in cyberspace (very nasty, more opportunities to shoot the black man), or are told, "Wait until we are ready to see you" - the caption to a roomful of empty chairs. Click on the "I'm off" spot or wait for ever.

My clicks kept sending me back to the same feisty blonde receptionist and her message: "Thank you for visiting Cyberspace. Have a nice day." Piper told me afterwards: "I think she's rather pleasant."

He gets his astonishing effects from a humble Apple Macintosh 8200 that cost him pounds 1,200 two years ago and the software packages Photoshop and After Effects.

CD-Rom /video art is about as little known in this country as black art. Piper and Sonia Boyce, Britain's leading black artists, are seldom reviewed outside the art press. As for Britain's white electronic artists, only Simon Robertshaw has gained mainstream acclaim, for his sequences of a rotting cow at the Natural History Museum.

Final embarrassment at the hands of Piper: his electronic exploration of black masculinity in Negrophilia, on a small screen right beside the RCA's reception desk. My first few clicks located a black man in flagrante with a white woman (cue soundtrack of female gasps), then the white female cliche, "To you I was always just a body", captioning an image of a black female nude. I made an excuse and clicked "Exit".

As an experience of identity, Gill Oliver's Fat Cow installation, one of the exhibits that had a four-day run in "Sight Unseen" at the Tannery Gallery earlier this month, was not much easier.

There were no electronics, but usherettes aided viewers in making a quick- click choice between two entry doors marked "Not thin" and "Not fat", rubber-stamping the backs of our hands accordingly.

The criteria for "Not thin", they explained to the perplexed, were a waist in excess of 34ins for men and a dress size larger than 14 for women. These days, even a size 16, the commonest size, is considered fat. You get the idea.

Through the doors, in a darkened room, hang a dozen suspended latex moulds of the head and torso of the artist, swaying in draughts of air from fans and illuminated by flashing green lights. Ms Oliver is 5ft 1in tall and weighs 16-and-a-half stone.

It was difficult to squeeze past the pale, puffy forms without touching them. Acrylic mirrors on the walls distorted them, while an audio track dispensed muffled insults, such as, "Look at the state of that!"

Ms Oliver is a social worker who runs a residential home and day centre for people with learning disabilities. She knows the damage mockery can do. This was her first installation and she was pleased with the response. Among the remarks in her visitors' book: "It hurt. Maybe only thin people should be allowed in." But why did some people kiss the moulds?

'Keith Piper: Relocating the Remains' continues at the RCA, Kensington Gore, London SW7 (0171-636 1930) to 13 August; the accompanying monograph and CD-Rom are available at the exhibition price of pounds 15