Fearless Gambler? Could Be Brain Damage
Harm to amygdala seems to impair 'loss aversion'
By Harry Kimball,  Newser Staff
Posted Feb 9, 2010 10:09 AM CST
A patient is examined during a scan.   (AP Photo)
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(Newser) – People with damage to their amygdala, a deep part of the brain that governs basic value judgments, are more likely than others to take big risks for uncertain payoffs. A new study pitted 2 women with amygdala-specific lesions against 6 controls in tests of their willingness to gamble. The control group went for it only if the return were 50% to 100% higher than the potential loss; not so with the brain-damaged participants.

Those with a damaged amygdala consistently made gambles with a smaller likelihood of gain, in some cases taking risks where the payoff was smaller than the potential loss. The loss of “loss aversion” fascinates the researchers. “It may be that the amygdala controls a very general biological mechanism for inhibiting risky behavior when outcomes are potentially negative,” one tells the BBC. He calls it a “basic evolutionary defense mechanism.”