Life's stresses may have a greater impact on decision-making in older adults than in their younger counterparts, a small study suggests.

The study, which measured people's risk-taking during a driving game, found that stress seemed to make older adults more cautious but had little effect on younger men and women.

The implication is that daily stress may affect older adults more so than younger people, at least in the context this study examined, lead researcher Mara Mather.

"Our findings suggest that stress makes older adults less risk-seeking in their decisions," said Mather, an associate professor of gerontology at the University of Southern California in Los Angeles. Whether this is a good or bad thing, she added, depends on the situation.

"In some financial situations, for instance, risk-seeking helps people earn larger returns," Mather said. "However, it can also lead to larger losses - as can be vividly seen in the recent stock market losses."

The study findings, published in the journal Psychological Science, are based on 45 men and women between the ages of 18 and 33, and 40 men and women between the ages of 65 and 89.

The subjects were randomly assigned to a stressful situation - submerging their hand in ice water for three minutes or submerging their hand in warm water for three minutes.

Afterward, all of the participants completed a simulated driving game in which they had to decide whether to run a yellow light that turned red at different intervals; they accumulated points for every second spent driving during the yellow, but lost points if the light turned red before they braked.

Mather's team found that in the group not exposed to the ice-water stress, older adults actually outscored younger ones. In contrast, older adults exposed to the stressful condition reduced their average score by nearly half, but the stressor had little effect on younger participants' scores.

Under stress, older adults became less sure of themselves, braking and restarting about three times more often than their younger counterparts, the researchers found.

Both younger and older adults showed a rise in the stress hormone cortisol after the ice-water challenge. It was their behaviour that differed.

Stress hormones affect brain regions involved in decision-making. Past research has found that these brain areas tend to shrink in volume as people age - which could potentially alter the effects of stress on decision-making, especially decisions about risk, Mather's team notes in the report.

The current results, Mather said, highlight a need for more research into how the impact of stress differs by age.

Reuters