Giacometti meets the Elephant Man as the Turner Prize puts controversy before quality

The Turner Prize does not make life easy for itself. Every year it has to come up with four youngish and interesting artists. There is a written rule that they must be under 50. There is an unwritten rule that they must not have been shortlisted before, and certainly must not have won, and a second unwritten rule that they must be "innovative". In other words, anyone with form is excluded. No wonder the prize must often make do with art that is no more than barely adequate.

And this, remember, is the premier annual national art prize.

The shortlist for the 2006 version was announced by the Tate director, Sir Nicholas Serota, yesterday. Tomma Abts, Rebecca Warren, Mark Titchner and Phil Collins are the four selected artists - a painter, sculptor, billboard artist and "social process" artist. They are all in their thirties or early forties, and their names may not be well known to you. In fact, it would not be a real disaster if they went on being unknown. But they are sort of OK.

Of course, what the prize lacks in quality, it can make up for in controversy. There was a little pre-controversy last week, when one of this year's judges broke their usual strict code of silence. She said she and her colleagues had not always seen the art they were supposed to be adjudicating, and that the Tate was content for them to make their minds up on the basis of catalogues and photos instead. Actually, no one in the art world will find this at all shocking. We all prefer catalogues.

But with this year's shortlist, the judges very likely have seen the work firsthand, because - by a coincidence - all four are also included in The British Art Show 2006. This is touring the country, and currently it is in Nottingham. So, if you want, before the Turner Prize show opens at Tate Britain in October, you too can go and see the foursome.

And I think Abts' painting is worth seeing. It has character. It has a tone you cannot quite catch. Her pictures are abstract, small, the same size. Their colours are subdued, their forms are curvy, zig-zaggy, interlocking, their surfaces have incisions and embossings, and there is some kind of weird game going on. Their patterns do not properly click, they are almost random, but they have hints of purpose and expression. There is a bit of comedy, a bit of anxiety. They are like complex little personalities.

Warren is much more explicit. Her figurative sculptures look like the love-children of Giacometti and the Elephant Man. They are made of claggy, blobby, drippy, slimy clay, mixed with impurities, suggesting sink blockage. They are monstrous and cartoony, deformed and in mid-meltdown, and you know exactly where you are with them, in the realms of the jokey-rude-gross-disturbing.

Titchner puts strident slogans on posters and billboards in blaring typography. They are nonsense slogans - "be angry but don't stop breathing" - but sound like propaganda, evangelism, self-help, or a hard-rock chorus. They play with ideals, utopias and belief systems in a knowing and amusing way. It is not a bad idea, but you can imagine someone else doing it more wittily.

Collins is a dull political artist (not a tautology, incidentally), who organises participation events for the oppressed, and videos them. The best known is a 48-hour disco marathon involving Palestinian youth in Ramallah. Very pointless, it seems to me, as art or activism, but he is lining up to be the "controversial" one.

Portraits of the artists

Tomma Abts

The German-born abstract artist, 38, who lives in London, was praised for a "rigorous and consistent approach" to painting. It is seen as having a physicality that gives it a curious three-dimensional effect, with paint thickly applied in places. Every title is derived from a dictionary of German first names.

Phil Collins

The artist, 35, who lives in Glasgow, creates photographic and video installations involving diverse social groups. His recent projects include a work called Baghdad Screentests, made in 2002 in the run-up to the Iraq war. Forty participants were recruited in Baghdad to sit silently for a series of Hollywood-style screen tests for a film that did not exist. Another work, They Shoot Horses, documented a disco marathon which he organised in Ramallah by paying nine Palestinians to dance for eight hours.

Mark Titchner

The Londoner, 33, is best known for his hybrid installations which explore modern belief systems. He creates posters, wall-paintings, sculpture and slogan T-shirts in which he interweaves references from pop lyrics to philosophy. He has combined song lyrics with the writings of Heidegger, and remade 1960s scientific devices out of hardware shop materials as a way of combining ideas.

Rebecca Warren

Her large-scale, cartoon-like sculptures are often sensual depictions of grotesquely voluptuous women which challenge the image of the idealised female subject in art history. The largely figurative work by the Londoner, 41, often involves exaggerated body parts such as giant breasts and bottoms which are overtly sexual but which also ridicule the "male gaze", according to the judging panel.

Arifa Akbar