Scientists in Cambridge studying the brains of problem gamblers have found that these individuals react much more strongly to "near misses" (i.e. a horse they backed to win actually coming second) than non-addicts. This misinterpretation of a miss as a hit may explain why gamblers keep betting even when they keep losing.
The result, published in the Journal of Neuroscience this week, surfaced when brain scientists Henry Chase and Luke Clark scanned the brains of gamblers playing a virtual fruit machine that paid out 50 pence whenever the images on the two reels matched.
When the subjects "won" like this, the regions of their brain rich in the pleasure chemical dopamine, including the brain stem and striatum, showed big spikes in activity. But even more intriguing was the finding that, when the subjects narrowly missed out on a win - for instance when like images on the reels were misaligned by just one notch, the gamblers' brains also registered an equivalently big surge in dopamine as though they'd won.
This effect was not present in the brains of non-gamblers, suggesting that gambling addicts keep on betting because the rewarding surges in dopamine they feel by convincing themselves they've always "nearly won" help to reinforce the gambling behaviour. The researchers hope that understanding these neurological underpinnings of problem betting will help in the development of behavioural and chemical ways to help addicts.