Stress Changes Older People's Minds More

Older people change their behavior more under stress than younger people, especially when risk in involved, according to a new study.

In an experiment, researchers at the University of Southern California held their hands in ice-cold water for three minutes. They then played a driving game where they had to decide whether to run a yellow light.

They started with a green light and were given points for time driven during a yellow and lost points when it turned red. They needed to take a risk to score, lead researcher Mara Mather said.

"This is the way life is, quite often. To make more money in your investments, you have to take risk. To end up dating someone, you have to take the risk of going up and saying hello," Mather said. "When there's a potential payoff, most of the time you have to take some risk."

The people in the test were in two age groups -- 18 to 33 years old and 65 to 89 years old. In groups not exposed to the cold water, the older people were better drivers and scored higher.

But when both groups were placed under stress, the older folks were more cautious and jerkier, braking and restarting three times as often.

The differences in the effects of stress were consistent even when the researchers accounted for gender, level of education, mood and health self-ratings.

"The everyday commute can be stressful: someone cuts you off, you're late already. Are you more likely to try and take a risk than if you weren't stressed out?" Mather asks. "Our results indicate that stress changes older adults' strategies."

The exposure to ice-cold water caused a rise in levels of the hormone cortisol, measured in saliva. Cortisol levels increased by about the same amount in younger and older adults.

"The brain regions that are involved in and activated by stress overlap quite a lot with the brain regions that are involved in decision making and, in particular, in decisions about risk," Maher said.