New insight into why gambling is so attractive to some

A new study demonstrates that when gambling, almost winning promotes significant recruitment of win-related circuitry within the brain and enhances the motivation to gamble.

The research, published by Cell Press in the February 12th issue of the journal Neuron, provides insight into why gambling is so attractive and may shed light on why some individuals develop a compulsion to gamble.

Despite the common saying amongst gamblers that "the house always wins," gambling remains a popular form of entertainment. Research has shown that near-misses (such as two cherries on the slot machine) and a sense of control over the game (such as the chance to throw the dice) promote gambling tendencies and may be associated with the addictiveness of gambling. However, little is known about the brain mechanisms involved.

"We devised a series of experiments to elicit near-miss and control phenomena in the laboratory and used functional magnetic resonance imaging (fMRI) to explore the brain mechanisms underlying these cognitive distortions," explains senior study author Dr. Luke Clark from the Behavioural and Clinical Neuroscience Institute at the University of Cambridge.

Dr. Clark and colleagues focused on the ventral striatum and medial frontal cortex, which previous research had implicated in processing rewards and drugs of abuse. They also examined associations between the level of activation in this circuitry during gambling and a subjective measure of gambling propensity.

Near-misses were associated with a significant activation of the ventral striatum and anterior insula, areas that were also activated by unpredictable monetary wins. There was a significant positive relationship between insula activity to near-misses and a questionnaire measure of gambling propensity that is significantly elevated in problem gamblers. Interestingly, the insula has been implicated in drug craving and other addictive behaviors.

Although near-misses were rated by subjects as more unpleasant than full-misses, they also increased the desire to play the game. These subjective effects were only observed when the subject had control over arranging the gamble. The interaction between near misses and personal control was also reflected in the fMRI data in the medial and frontal cortex.

"Gamblers often interpret near-misses as special events, which encourage them to continue to gamble. Our findings show that the brain responds to near-misses as if a win has been delivered, even though the result is technically a loss," offers Dr. Clark. "By linking psychological and neurobiological accounts of gambling, these data inform our understanding of gambling behavior within society, and by extrapolation, the capacity of gambling to become addictive and pathological."