Study provides new understanding of excessive gambling

May 8 2007

People process information about financial loss through mechanisms in the brain similar to those used for processing physical pain, according to a new imaging study.

The results could provide a new understanding of excessive gambling.

The new study detected activity in the striatum, a region that processes signals in the brain's system of reward and defensiveness. Previous studies had shown activity in the striatum increasing when subjects were awarded money, but falling silent when subjects lost money. The new study's lead author, Ben Seymour, MD, and colleagues at the Wellcome Trust Center for Neuroimaging in London suggest that the negative value people associate with losing money stems from an evolutionarily old system involved in fear and pain. This could provide some biological justification for the popular concept of "financial pain." Their study was published in the May 2 issue of The Journal of Neuroscience .

"This work extends our understanding of how the striatum processes both gains and losses and why other experiments have had difficulty eliciting the striatum's involvement in losses," says Read Montague, PhD, at the Baylor College of Medicine, who did not participate in the research.

In the study, 24 subjects, 13 male and 11 female, learned to associate abstract image cues with a specific amount of money: 50 pence (equivalent to $1) or £1 ($2). The researchers recorded their brain activity over 200 trials as they showed subjects first the original image then an outcome screen indicating whether they had won the associated amount of money, lost it, or received nothing.

The imaging results showed that areas of the striatum toward the front of the brain were more active when subjects did better than they expected, or when they were relieved not to lose as they had expected. Losing money or receiving less than they expected based on the previous association elicited activity in areas of the striatum toward the back of the brain. The findings bolster previous evidence from animal research indicating a gradient of reward- and aversion-based activity across the striatum from front to back.

"Although an impressive amount is known about how the brain learns about financial gains, many previous studies have failed to identify any specific system for dealing with losses," says Seymour. "Understanding how these two systems operate and interact may provide important insights into why some people gamble more than others, and why some become addicted to it."