How to behave in a gallery

At least you knew where you were and how to behave in the old-style temples of art. The paintings looked like paintings - which looked like something recognisable - and your eye followed the order of the labels around the walls. You spent, according to a much-quoted statistic, approximately 15 seconds looking at a painting and about 30 looking at its label. Sculpture was the thing that got in the way when you stepped back to gain a perspective on the paintings. There was a clear route marked on the museum plan, and you knew your task was complete when you were steered towards the gift shop to buy a souvenir postcard.

It's more disorientating in the contemporary gallery, where the paintings aren't always fixed to the wall, and what we're looking at might not be paintings. At the South London Gallery, Christian Boltanski has made an installation of 3,000 telephone directories from around the world.

The sentiment is clear - all of humanity is contained herein. But do you just look, or do you dare to look someone up? It's obvious that just gazing at the exhibits is not enough, that an artist today expects you to play a part in the installation. But what is the part you are meant to play?

I became uncomfortably aware that this is a problem for some people when I took a friend to the opening of Sam Taylor- Wood's exhibition at the Hayward last week. Open the door to the gallery and you enter a world of excess information. Films are already playing, in continuous loops. Sounds and images from one video installation spill into another. One piece might have several projections running concurrently.

For those in the contemporary art world, it's just another day at the office, but my friend didn't know where to begin. Videos present a particular problem that illustrates a more serious confusion created by a contemporary show. How and where are we supposed to look? Where does it begin or end? Surely, the artist can't expect us to sit through it all?

Some expect just that. One of the finest contributions to the last Venice Biennale was João Penalva's rich and complex installation, R. Now, Penalva is perhaps the most meticulous artist I know, and he was worried that no one would devote enough time to experiencing the sequence of video installations, objects, images and texts that he had worked on for more than a year.

As the complimentary Bellinis chilled out in the giardini, João informed me that one needed at least two and a half hours to do justice to his show. Reader, I missed the canapés. I am saddened to report that most of my colleagues did not.

I wish there were something we might call gallery etiquette, but contemporary art breeds an uncertainty that comes with the materials it employs and the places it employs them. It seeks to undermine our expectations, so we're never going to be quite equipped for it.

Nevertheless, the objects of an exhibition, video or not, are installed for the benefit of the viewer. And, increasingly, artists

have tried to bring the viewer into the picture, as it were, to understand how the art works from the inside out.