When gambling, people dwell more on losing big than winning big, a new study finds.

Using a brain scan technique called functional magnetic resonance imaging (fMRI), researchers at UCLA mapped the brain's responsiveness as people placed bets in a gambling game.

Participants were given $30, and then asked whether they agreed to each of more than 250 gambles in which they had a 50-50 chance of either winning one sum of money or losing another.

Would they, for example, agree to a coin toss in which they could win $30 or lose $20?

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The participants had four choices for each gamble: strongly accept, weakly accept, weakly reject or strongly reject.

Results showed that, on average, participants had to be offered a 50 percent chance of doubling their money before they were willing to place a bet.

Wired to wager

By looking only at a participant's brain activity as they decided whether or not to place a bet, the researchers could predict what that person would ultimately do.

"The people who show much more neural sensitivity to losses relative to gains are the same people who are very reluctant to gamble unless they are offered extremely favorable gambles," said study team member Craig Fox. "The people who are about as sensitive to losses as gains neurologically are the ones who are more willing to gamble."

Those people most willing to gamble were least turned on as the stakes got higher, while the people most averse to gambling were most turned on as gains and losses increased.

Reward centers

The study, detailed in the Jan. 26 issue of the journal Science, also revealed that people respond more strongly to potential losses than potential gains.

Thinking about the possibility of winning money turns on some of the same areas of the brain that are activated when people take cocaine, eat chocolate or look at a beautiful face, explained study team member Russell Poldrack.

These "reward centers" of the brain that get turned on when we think about winning money get turned off when we think about losing money.

"You turn down the reward areas of the brain, and you turn them down more strongly for losses than you turn them up for gains," Poldrack said.

The brains of most people, for example, will respond more strongly to a $100 potential loss than a $100 potential gain.

Indecent proposals

Past studies have found that most people are "risk averse," tending more towards the side of caution when weighing future actions. The new findings provide the first neural support of this pattern.

This human tendency extends beyond gambling, the researchers say.

A woman in a bad marriage, for example, is not likely to leave unless she has prospects that are much better than her current situation, said lead author Sabrina Tom.

"She's probably not going to leave for something that's only moderately better," Tom said. "She needs to know it's going to be a lot better before giving up what she already has."

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