Science: I think therefore I paint

Artists' thought processes, as well as the way they move their eyes and hands, are quite different from those of the rest of us. By Steve Connor

ARTISTS THROUGHOUT history have had a reputation for being unconventional. Now science seems to support this prejudice. A study of the way artists draw objects has shown that they really do use their bodies differently from the rest of us.

John Tchalenko, a former lecturer at Imperial College in London, has carried out the first detailed research into the movements and thought processes that underpin the way artists create impressions of the world they see. His results show that when it comes to drawing a picture, artists call upon quite novel ways of co-ordinating their hands, eyes and brains.

Dr Tchalenko approached the task with the help of two techniques and a long-time friend, the artist Humphrey Ocean. He used a device called an eye-tracker, which was able to plot the precise movements of Ocean's eyes as he drew a portrait. The second approach was to employ a brain- scanner to discover which parts of Ocean's brain became active during a drawing exercise.

"I'm interested in creativity, and the way that the visual input is transformed into the manual input - therein lies the creative process," Dr Tchalenko says.

Ocean was asked to draw a portrait while wearing the eye-tracker device - which looks like a bicycle helmet attached to space-age goggles - at the Sensorimotor Control Laboratory at Oxford University. Ocean wore the device for about 12 minutes at a time. A sensor recorded his hand movements, and how these were co-ordinated with the exact motions of his eyes. A non-artist carried out the same tasks for comparison.

Most people's eyes are continuously moving in their sockets, at a rate of about 140 flickers a minute, in order constantly to shift the scene they are viewing over the central - and most sensitive - part of the retina. When non-artists were placed in the eye-tracker and asked to draw a face, they continued to follow this pattern, fixing their eyes on a particular spot on the face for about one third of a second.

Ocean's eye movements during drawing, however, were significantly different. From a fixation rate of 140 a minute he went down to about 10 or 12 fixations, each one lasting, of course, considerably longer. His eye movements over the face of the subject were also less erratic and more controlled. Ocean was moving his gaze at a speed estimated to be about 40km per second and he was able to fix his interest on a spot on the face with pinpoint accuracy - whereas the non-artist's gaze wandered all over the subject.

"It shows that an artist looks at a face methodically," Dr Tchalenko says. Ocean's hand movements were also significantly different from those of a non-artist. Ocean would move his hand several times over the paper before committing himself to drawing a line. It was as if he were rehearsing his actions.

The next phase of the study was to see how Ocean's brain was working during the drawing process. For this, he was placed in a functional magnetic resonance imaging (fMRI) scanner at Stanford University in California. While lying in the scanner, Ocean was asked to draw portraits from six photographs, and six geometric figures. Subtracting the brain activity used in one activity from that used in the other should yield the mental activity needed to portray a face. The results show a clear difference from the way non-artists draw faces.

The visual information from the eye enters the visual centres at the back of the brain in both artists and non-artists, and then travels forward to the frontal areas of the cerebral cortex - the "higher" centres, which are involved in more abstract thought processes.

"In Humphrey's case, activation occurred in the right frontal region of the brain, whereas in the non-artist controls it occurred in the posterior region. It appears that Humphrey was `thinking' the portraits, while the controls were slavishly copying them," Dr Tchalenko says.

The study, which is described in an exhibition opening today at the National Portrait Gallery in London, clearly indicates that artists have learnt to use their brains, as well as their hands and eyes, quite differently from the rest of us. Dr Tchalenko says that the next step in the research would be to see how art students learn this skill over a period of years.

The Painter's Eye, sponsored by the Wellcome Trust, can be seen at the National Portrait Gallery, London from today. Admission is free