A new study from Cambridge University in the U.K. has identified a part of the brain that appears to play an active role in compulsive gambling. The study, led by Dr. Luke Clark of Cambridge, was published in the Proceedings of the National Academy of Sciences (PNAS).
The Cambridge researchers found that brain damage affecting the insula — an area of the brain linked to emotion — makes people more likely to quit while they are ahead rather than continue gambling.
The damage to the brains, whether it came from strokes or tumors, disrupted the errors in thinking found in a healthy brain that contribute to compulsive gambling. These errors in thinking, sometimes referred to as the “gambler’s fallacy,” are cognitive distortions that lead people to believe that near misses bring them closer to winning. This mistaken belief can be so strong that previous research has found gamblers get the same kind of rewarding feeling from a near miss as they do from a win.
“A healthy brain is actually functioning incorrectly by thinking that they are more likely to have a tail after say, four heads,” Dr. Clark said in a news release from the university. “Those with insula injuries were very rational.”
The Gambler’s Fallacy
There are two kinds of cognitive distortions that can encourage people to keep gambling when it would be wiser to stop. The first is the belief that a certain outcome makes the opposite outcome more likely the next time. For example, this error in thinking leads people to believe a coin flip that comes up heads the first time will be more likely to come up tails the second time, when in fact the odds are still 50-50.
The second kind of error leads people to believe that an almost-victory brings them closer to a real victory. They may believe that an almost-flush in poker is more likely to yield a real flush or another strong hand the next time, or that two matching pictures on slot machine make it more likely that they will get the three pictures needed for a jackpot soon.
Scientists have come to believe that people who become compulsive gamblers are more likely to experience these cognitive distortions. Dr. Clark’s study hoped to find a possible explanation for susceptibility to the gambler’s fallacy.
Zeroing In on the Insula
Dr. Clark and his team conducted their research with the assistance of study subjects who were all suffering from injuries to specific areas of the brain. Some had damage to the amygdala, some had damage to the ventromedial prefrontal cortex and some had damage to the insula. The study also included a control group consisting of people with no known injuries to the brain.
The healthy participants and the brain-damaged participants were each invited to play a roulette game and a slot machine game. The roulette game involved placing bets on red or black to test for the presence of the “coin-flip” distortion. The slot machine game was programmed to produce both wins and near misses, to see if these near misses encouraged the patients to continue.
The researchers found that all but one of the groups in the study reported similar levels of increased motivation to continue gambling after near misses, and were more much likely to bet on the color opposite to that of the previous spin when playing roulette.
The exception was the group that had suffered injuries to the insula region of their brains. This group reported much lower rates of the cognitive distortions that seem to be responsible for dictating the way people bet or encourage people to keep gambling in the belief that success is just around the corner.
As a result, Dr. Clark and his team concluded that the insula plays a key role in the thinking that encourages people to gamble. They suspect that a hyperactive insula could explain why gambling develops into an addiction for some people. If this is the case, targeted psychological or medicinal treatment to moderate hyperactivity in the insula could be an effective treatment for people who suffer from gambling addiction.
The insular cortex is more commonly referred to as the insula. It is a section of the cerebral cortex, or the “grey matter” of the brain. The insular lies deep under the parietal, frontal and temporal lobes of the brain, and is responsible for some cognitive functions and for visceral or “deep” functions of the brain, such as regulating emotions and motor control. The insula also plays a role in pain sensations, touch, taste and smell.