Brain :: Hhow our brains evaluate the possibility of gaining versus losing

Should you leave your comfortable job for one that pays better but is less secure? Should you have a surgery that is likely to extend your life but poses some risk that you will not survive the operation?

Should you invest in a risky startup company whose stock may soar even though you could lose your entire investment? In the Jan. 26 issue of the journal Science, UCLA psychologists present the first neuroscience research comparing how our brains evaluate the possibility of gaining versus losing when making risky decisions.

Participants in the study, mostly UCLA students in their 20s, were given $30 and then asked whether they would agree to each of more than 250 gambles in which they had a 50-50 chance of winning an amount of money or losing another amount of money. Would they, for example, agree to a coin toss in which they could win $30 but lose $20? While the 16 participants were considering the possible wagers, they were in a functional magnetic resonance imaging (fMRI) scanner at UCLA’s Ahmanson?Lovelace Brain Mapping Center, where researchers studied their brain activity; the technique uses magnetic fields to spot active brain areas by telltale increases in blood oxygen.

For each question, the participants answered whether they would strongly agree to the gamble, weakly accept it, weakly refuse it or strongly reject it. Participants were not told whether they had won or lost until after they left the scanner; afterwards, the researchers randomly selected three of the gambles, and if the participants had previously agreed to accept those, the researchers flipped a coin and the participants either won or lost the money. What interested the researchers, however, was the activity of the brain’s regions during the decision-making process, not the subject’s reaction to winning or losing.

On average, participants needed to be offered a 50 percent chance of winning about $19 to risk losing $10, but that amount varied widely among the subjects. One subject, for example, needed the chance to win $60 to risk losing $10, while another needed only the chance to win $11 to risk losing $10. The researchers could predict people’s tolerance to risk by analyzing their brain patterns.

“Looking at how your brain responds to potential gains versus potential losses, we can predict how risk-averse you are going to be in your choices,” said study co-author Russell Poldrack, UCLA associate professor of psychology, who holds UCLA’s Wendell Jeffrey and Bernice Wenzel Term Chair in Behavioral Neuroscience. “Brain activity predicts behavior.”

“Individual differences in brain activity correspond very closely to individual differences in participants’ actual choices,” said co-author Craig Fox, an associate professor of policy at the UCLA Anderson School of Management and an associate professor of psychology. “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. The people who are about as sensitive to losses as gains neurologically are the ones who are more willing to gamble.”

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, Poldrack said.

The researchers studied which parts of the brain became more active or less active as the amount of money participants could win or lose increased. Regions that become more active as the amount increases are considered “reward centers” in the brain, such as the prefrontal cortex and the ventral striatum, Poldrack said.


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