In gambling, brain explains attraction of near-misses

You pull the lever on the slot machine and get two strawberries and an apple. Or you throw down dice and get a six, then an eight, when you were aiming for a seven. So close! Play again!
We get a rush from playing games that we feel like we've almost won, but have lost by a small margin. For people who gamble, the allure of the "near miss" can keep the dice rolling, the slots turning, and the money slipping away.
A new study in the Journal of Neuroscience looks deeper into the mind of the gambler. Psychology researchers Henry Chase and Luke Clark looked at 20 regular gamblers. Participants varied from recreational gamblers to "pathological gamblers," meaning their habits may interfere with everyday life.
Researchers scanned the brains of these gamblers while they performed a simplified slot machine task. Although the sample size is small, studies that make use of functional magnetic resonance imaging (fMRI) tend to have fewer participants than survey-based experiments, and can still have important implications.
The study found that near-miss outcomes during gambling involve the brain's reward system; in particular, areas called the ventral striatum and the anterior insula.
A previous study on healthy volunteers also found that near misses are linked with heightened activity in these same brain regions associated with monetary wins.
Scientists have long known that a small cluster of brain cells that release a chemical called dopamine have been associated with addiction, but there has never been a clear explanation for it.
"This study provides an important advance in our understanding of how the brain's reward circuits underlie one form of addictive behavior, pathological gambling," said Steven Quartz, director of the California Institute of Technology’s Brain, Mind, and Society Ph.D. program, who was not involved in the study. "Many modern games of chance, especially slot machines, compel some people to play repeatedly even when they are not winning," he said in an e-mail.
Chase and Clark also showed that the more severe a person's gambling is, the more these near misses trigger the reward circuit. But the brain region in question is also involved in learning. That means the gambler's brain may be "tricked" into thinking that it is learning new information about the environment through near misses, Quartz said.
"Ultimately, a better understanding of the rewarding effects of near misses may have implications for both treating problem gambling and for regulatory practices of the gambling industry," he said.
The authors noted that they did not take into account such conditions as nicotine dependence and personality disorders, which may have impacted the brains and behaviors of participants. Also,the group of regular gamblers in this study was almost all male.
Further research is necessary to determine more conclusively how the minds of gamblers work.