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Scientists have identified a small area of the brain that seems to play a big role in how we think about risk. NPR's Jon Hamilton reports on what scientists have learned about risky behavior from two gambling monkeys.
JON HAMILTON, BYLINE: These rhesus monkeys play for juice. And Veit Stuphorn, a brain scientist at Johns Hopkins University, says they're really into it.
VEIT STUPHORN: (Laughter) Yeah, they do like to gamble, actually.
HAMILTON: So Stuphorn's lab had the monkeys play a gambling game while monitoring the activity in their brains. The game had two options. Option one offered a juice reward that was guaranteed but usually small. Option two was a gamble. Stuphorn says it might bring a lot of juice or none.
STUPHORN: And the monkey had to choose every single time whether he wanted to have the gamble or the sure thing.
HAMILTON: Stuphorn says the experiment confirms something other scientists have noted about gambling monkeys.
STUPHORN: They're always tempted to go for it. They're going for the big win.
HAMILTON: Even when safe bets would have won them more juice. Stuphorn's team suspected that this preference for long shots was linked to a small patch of brain in the prefrontal cortex. When a monkey won big, brain cells in this area got really active. But that didn't prove these cells were affecting the monkeys' behavior. So the researchers did another experiment that temporarily inactivated this brain area by cooling it. Then they let the monkeys continue playing the juice game. And Stuphorn says the animals' behavior changed.
STUPHORN: They did not like the gambles anymore so much - that had the large variability. Instead, they went for gambles with - it was a smaller range of outcomes.
HAMILTON: In other words, they took safer bets. Stuphorn says the finding adds to a body of research that is challenging an old idea about risky behavior.
STUPHORN: For a long time, people thought that this is something like a personality trait, that some people are risk takers and other people are not so risk-seeking.
HAMILTON: But this study suggests that an individual's risk preference can be changed simply by increasing or decreasing the activity in one area of the brain. Stuphorn says that probably means our brains are constantly adjusting our desire to take risks, depending on the situation. That view is shared by Alireza Soltani who studies decision-making at Dartmouth College. Soltani says gambling monkeys probably take big risks because the stakes are so low.
ALIREZA SOLTANI: The monkeys are playing for a drop of juice, and that's not a big deal.
HAMILTON: Soltani says other studies have found that when the stakes are higher, both monkeys and people are more likely to hedge their bets. And he says this emerging idea that the brain is constantly adjusting our view of risk has big implications for society.
SOLTANI: If you look at risk preference as not something that are fixed and set in stone, then we can actually think about what we can do to help people to change their risk preference towards something that is better for them.
HAMILTON: Like not texting while you drive. The monkey study focused on a brain circuit that's involved in eye movement. That's because the game had the animals move their eyes to make choices. But Michael Platt of the University of Pennsylvania says there may be many other risk circuits in the brain that influence other risky movements.
MICHAEL PLATT: Whether that's reaching out to pull the handle on a slot machine or walking to the casino in the first place.
HAMILTON: And Platt says understanding these circuits could have some practical applications.
PLATT: One would be to help people who have decision-making disorders, whether that's problem-gambling or addiction or other things like that. So we might be able to develop more effective therapies.
HAMILTON: Also, Platt says, if we understand why our brains sometimes encourage risky behavior, it could help all of us make better decisions. Jon Hamilton, NPR News.
(SOUNDBITE OF BUD POWELL'S "COLLARD GREENS AND BLACK EYED PEAS")
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