Moira Jeffrey reports on a brace of Glasgow exhibitions by two

double acts that are raising the profile of artistic collaboration

Sonny and Cher; John and Yoko; Little and Large. It can be hard to make up your mind about double acts. Are they twice as nice or double the trouble? Two new exhibitions in Glasgow - one at Transmission Gallery, the other at the Lighthouse - raise the whole question of artistic collaboration this week.

In visual arts it was once hard to find the kind of pairings taken for granted in popular songs or end-of-the-pier comedy. But these days pairs are everywhere. Where once Britain only had Gilbert and George, now there are the twin video artists Jane and Louise Wilson; kings of shock art Jake and Dinos Chapman, and dozens of less sensationalist collaborators.

In 1999 someone curated a show called Art Lovers, where artist couples who don't usually work as duos made art together. It included some of the couples of the British art scene, such as Sarah Lucas and Angus Fairhirst, Tracey Emin and Mat Collishaw. There was, of course, a faint whiff of Posh 'n' Becks about it and one can't help wonder if they regret it now.

Dub'l InTROODer, at Transmission, is a show all about duos

and includes artist pairs such as London outfit Bank which is now a twosome but started out as a collective running an independent arts space and a satirical tabloid freesheet. Its anonymous collective identity always suited the rather provocative nature of its onslaughts on the art world.

John Beagles and Graham Ramsay, the Morecambe and Wise of the Scottish art scene, have contributed a kind of Anderson shelter of ideas; an industrial unit stuffed with their collection of satirical wind-up toys, like Hamish the Tartan Tearaway, their prototype for a Wembley turf-tearing action doll.

The Transmission basement is always a chilly, depressing place and so it's perfect for the most important participants, the grim brothers of American video art, Mike Kelley and Paul McCarthy.

Both these artists come from California and it's as though the relentless sunny optimism of the west coast has driven them to make their own subject despair.

McCarthy is one of the key figures in exploding the myth of the romantic artist, which had held America in its thrall since the advent of abstract expressionism. His early work was messy, pathetic, and excruciating to watch. Like a hideous parody of the famous images of Jackson Pollock at work in his studio or Yves Klein getting naked ladies to roll around in blue paint. It's currently on show in this country in I am Making Art, a survey of key video pieces from the seventies, at the Anthony Wilkinson Gallery in London. Kelley is an artist who loves effluvia, bodily substances, and general mess, so this is a match made in the underworld.

The joint video work, Heidi, confirms your every fear about video art on the subject of dysfunctional families. Set in a makeshift shed, the piece includes lots of blonde wigs, anguish in a hayloft, and unspeakable activity with sausages. It's relentless, repetitive, and stomach-churning. At a time when Hannibal Lecter is portrayed as an admired intellectual with an expertise in Florentine art, work like this messy, scary angstfest is probably still essential, but it's absolutely no pleasure to sit through.

It seems a million miles away from this basement nightmare to the cheerful top floor of Glasgow's Lighthouse and Moth, a collaboration between musician Brian Eno and artist Russell Mills.

Eno, the former member of Roxy Music who will not join the band's reunion tour, is famous for being ahead of his time and as the man who invented ambient music. Mills was responsible for some of the great graphic works of the eighties. His book covers for Picador and Faber included the first UK edition of Milan Kundera's Unbearable Lightness of Being. His album designs for bands such as the Cocteau Twins always added extra frisson to the excitement of buying records.

Mills has always been more than a designer for hire and his collaborations extend to installation, music, stage sets, and performance. His work can seem a little anodyne at times but it's the product of relentless intellectual and technical curiosity. In a talk last Saturday to a design conference at The Lighthouse, Mills managed to discuss the novel Tristram Shandy, the invention of reading glasses, and a brief moment from the Benny Hill Show all within a few sentences.

Moth is a suspended cocoon of crushed paper and polystyrene that rotates to randomly generated sound and light. It's highly mobile and deliberately unpredictable. It's a gentle piece of installation art and reminds me of my yoga teacher's description of meditation as ''dental floss for the brain''. Like meditation, this ambient sculpture can clean out some of these forgotten, dusty corners of the mind.

Just what makes people choose to work in twos rather than go solo? ''We have a strange relationship,'' Mills told the audience about his collaboration with Eno. ''We use each other as a sounding board.''

Sometimes, as in the case of Bank or Beagles and Ramsay, collaboration enables you to achieve things that would otherwise be exhausting, such as continuing to make and show art when you're stony broke. It also makes a clear political point that these days an artist is no longer a lone genius.

But you can't help suspect that it's also a matter of fun. You find someone who likes doing your kind of thing - whether it's wearing a blonde Heidi wig or making hi-tech music - and get on with it as consenting adults. When times are hard you can look across at each other in Sonny-and-Cher style and sing in consolation: ''I got you babe.''

l Dub'l-inTROODer is at Transmission, Glasgow, until March 31. Moth will be at The Lighthouse, Glasgow, until the beginning of April.