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This Part of Your Brain Makes You Fall for Casino Tricks

Scientists may have figured out which part of the brain makes us think we can win roulette. It's part of the same knot of neurons linked to love and hunger.
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(Photo: Wikimedia Commons)

(Photo: Wikimedia Commons)

It's not just the scintillating lights, absent clocks, and free-flowing booze that coerce you to continue the irrational act of gambling—against all odds—on chance-based games when you visit Vegas. New research suggests it's also the bedeviling work of a prune-sized hunk of gray matter that's folded deep inside your cerebral cortex.

The insula is a small part of the brain, but it packs an emotional punch. It helps us feel some of our most powerful feelings, including love, anxiety, and hunger. Patients who damage their insula can experience these emotions and cravings in unusual ways. And that makes them highly sought after for trials by scientists—researchers who want to understand how this slice of the neuron pie affects our daily lives. High-profileresearch published seven years ago, for example, showed that these patients had an easier time than others in kicking cigarette addictions.

The insula is a small part of the brain, but it packs an emotional punch. It helps us feel some of our most powerful feelings, including love, anxiety, and hunger.

Neuroscientists also want to know which parts of the brain are responsible for the gambler's fallacy. That's the bank account-draining delusion that the outcome of one spin of a roulette wheel can affect the outcome of the next. This fallacy can keep us optimistically glued to our sticky casino chair. It convinces us that we can enrich ourselves by throwing chips on one color or another as the croupier grabs the roulette wheel—we think we're seeing a pattern where there is nothing but randomness. The fallacy also misleads us into mistaking a near-miss on a slot machine as a sign that we're close to hitting a jackpot.

British and American researchers simulated gambling games with patients whose brains had been injured in different ways. They also ran the same experiments with neurologically healthy subjects. They measured how outcomes of roulette and slot machine spins affected gambling decisions, such as whether a mock gambler was motivated to try their luck with another round.

They found that insula-damaged patients had a wallet-shielding immunity to the gambler's fallacy—one that was lacking in everybody else.

When playing a slot machine, a near miss made most of the test subjects want to try again. This irrational response was "selectively absent in the insula group," the scientists write in a paper published this week in the Proceedings of the National Academy of Sciences.

And when the ball in the roulette wheel landed on the same color several times in a row, most of the gamblers threw their hypothetical chips onto the other color, mistakenly thinking that color's time was overdue. Again, "the insula group did not manifest this avoidance of recent outcomes," the researchers write.

The findings could help lead to a cure for problem gambling.

"If insula damage abolishes gambling distortions, then we expect the insula to be hyperactive in problem gamblers," says Luke Clark, a co-author of the study who lectures at the University of Cambridge's psychology department. "We're testing this hypothesis in an ongoing study. If true, this would open up new avenues for treating gambling addiction by reducing the insula hyperactivity."