Emotional judgments seek respect.

Like milk left out in the midday sun, judgment curdles when exposed to the heat of emotions, according to folk wisdom. A new study, however, concludes that a brain structure deeply enmeshed in emotion lends insight to risky decisions.

The results support a theory that emotions incited by the rewarding or punishing outcomes of risky decisions generate physiological responses--such as a racing heart beat and a queasy gut--that then act as cues for making future choices.

Decision making relies on the amygdala--an inner-brain area that helps regulate emotion--and a separate frontal-brain region, says a team of neuroscientists led by Antoine Bechara of the University of Iowa College of Medicine in Iowa City.

"Our findings suggest that the amygdala is a critical structure in a neural system necessary for ... implementing advantageous decisions," Bechara's group concludes in the July 1 JOURNAL OF NEUROSCIENCE.

The scientists studied 13 healthy adults, 5 patients with extensive amygdala damage, and 5 patients with frontal-brain damage that disrupts decision making (SN: 3/22/97, p. 183).

All participants completed a task in which they turned over cards from four decks, one card at a time, to find those bearing cash rewards and to avoid those carrying cash penalties. The researchers arranged two decks to yield an overall profit and two decks to generate a financial loss.

Although all participants had normal IQ scores, both groups of brain-damaged patients lost money on this task, while most healthy volunteers picked cards that produced a profit. Moreover, healthy volunteers displayed lowered skin resistance to a mild electric shock--a sign of physiological arousal--as they considered picking from riskier decks. The healthy participants thus may have used emotion-related bodily responses as decision guides, the scientists argue.

Frontal-lobe patients did, however, show signs of physiological arousal after selections, but amygdala patients did not.

Amygdala damage may disconnect emotionally charged bodily states from specific experiences, the researchers hold. As a result, they say, these patients may walk into oncoming traffic or act in other potentially dangerous ways. Destruction of the frontal-lobe area makes it hard to integrate related physiological responses, such as those experienced during card selection, they theorize.

Edmund T. Rolls of the University of Oxford, England, challenges this proposed anatomy of decision making. He argues that the amygdala and related frontal-brain regions mediate conscious feelings, but other neural areas that have little to do with judgment handle bodily responses to emotions.

Physiological states may sometimes steer risky decisions, comments Elizabeth A. Phelps of Yale University. But patients with amygdala damage often exhibit no serious decision-making problems, she says, raising doubts about whether that structure plays a pivotal role in judgment.