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June 7, 2001 Peter Shizgal studies the brain in the act of gambling




Peter Shizgal

Peter Shizgal, Director, Centre for Studies in Behavioural Neurobiology

Photo by Christian Fleury

by Barbara Black

Peter Shizgal, director of Concordia’s Centre for Studies in Behavioural Neurobiology, developed a gambling game with a colleague to study the way various parts of the human brain respond to the anticipation of winning money.

It was a novel application of the psychology of judgement and decision to mapping brain function. Dr. Shizgal and his co-researchers found that discrete parts of the brain respond in an ordered fashion to the anticipation of money.

The team also comprised Hans Breiter, Itzhak Aharon and Anders Dale, of Massachusetts General Hospital, and psychologist Daniel Kahneman, of Princeton University. Their results were published last week in the journal Neuron, and subsequently made the National Post and the front page of the Boston Globe.

In the experiment, conducted at the Massachusetts General Hospital, 12 volunteers were given $50 and told that they might lose some or all of it, keep it, or increase it. The subjects’ brain activity as they played the game was monitored through a neuro-imaging process called high-field functional magnetic resonance imaging, or fMRI.

Each subject was shown a sequence of spinners divided into three sectors, each with a different monetary value. They watched an arrow spin and then stop on one of the sectors to deliver a gain or loss. Their brain activity was measured during anticipation and when they realized, or processed, the outcome of their spin.

The results showed that multiple areas of the brain are engaged during assessment of potential gains and losses. In fact, an incentive unique to humans—money—produced patterns of brain activity that closely resemble patterns seen previously in response to other types of rewards, such as addictive drugs.

The finding that common brain circuitry is used for various types of rewards suggests that scientists may one day be able to use brain scans to measure our subjective responses, such as our likes and dislikes. It may also help scientists understand impulse-control disorders, such as drug abuse and compulsive gambling.

Their experiment incorporated ideas from decision affect theory, developed by Barbara Mellors and colleagues in the 1990s, and prospect theory, developed by Kahneman and Amos Tversky in the 1970s. Prospect theory has profoundly influenced the development of behavioural economics.

Aspects of these theories can be illustrated with the example of a person who thinks she is getting a raise of $5,000 a year, but gets only $2,000—and while she is getting a raise, is disappointed. Another example would be the person who believes he is going to be fired, but simply has to take a pay cut—and rejoices at his lucky break. Similarly paradoxical reactions happened in the gambling experiment.

Dr. Shizgal said that he undertook the gambling experiment because it was the easiest way to study evaluation and decision-making with the highly technical equipment now available. A lot of scholarly work has already been done on the psychology of evaluation, he said, and money was an obvious choice of incentive for human subjects.

He is well aware that gambling is a deeply troubling social problem—not only for individuals, who can lose everything they hold dear in a weekend, but for governments, who are now addicted to the revenue. However, he advises caution to those who think a cure is around the corner.

“Brain imaging is a powerful and fascinating technique, but it is insufficient in itself to tell us what parts of the brain are responsible for different functions. In order to draw strong conclusions, we also need data from studies of people who have suffered brain damage, as well as from studies of laboratory animals,” Shizgal said.

“Even if we do succeed in developing a good neurological account of impulse-control disorders, effective treatments are not guaranteed. However, we may well have a better chance of developing such treatments if we can understand the processes in the brain that determine impulse control.”

One study on a normal population is just the beginning. Shizgal looks forward to experiments that would, for example, compare self-controlled groups—gamblers who can get up and walk away—to groups with no such control.

A final note: In our stories in CTR about the future occupants of the new Science Complex, we have omitted the Centre for Studies in Behavioural Neurobiology, an outstanding research centre.