Pensioners are more caring

"Increasingly, it appears that the meaning of late life centres on social relationships and caring for and being cared for by others," said psychologist Professor Robert Levenson, from the University of California at Berkeley.

"Evolution seems to have tuned our nervous systems in ways that are optimal for these kinds of interpersonal and compassionate activities as we age."

In one study, the scientists looked at how 144 healthy adults in their 20s, 40s and 60s reacted to neutral, sad and "disgusting" film clips.

Participants were asked to adopt a detached and objective attitude, show no emotion, or focus on the positive aspects of what they were seeing.

The findings, published in the journal Psychology and Aging, showed it was easier for older people to see negative scenes in a positive light.

This is a recognised coping strategy that draws on life experience and lessons learned from the past.

By contrast, young and middle-aged participants were better at "tuning out" and diverting attention away from the unpleasant films.

Such "detached appraisal" draws heavily on brain functions responsible for memory, planning and impulse control that diminish with age. All three age groups were equally good at clamping down on their emotional responses when they had to.

Prof Levinson pointed out that, contrary to popular belief, heightened sensitivity to sadness does not indicate an increased risk of depression.

In fact, it is a healthy sign. "Sadness can be a particularly meaningful and helpful emotion in late life, as we are inevitably confronted with and need to deal with the losses we experience in our own life and with the need to give comfort to others," he said.

Weird Science Factoid: Most toilets flush in E flat.