An optimistic outlook may be good for your mental health as you get older, according to a new German study.

Dr. Stefanie Brassen and her colleagues at the University of Hamburg in Germany found that those with light-hearted and optimistic attitudes age better than others.

A sunnier disposition may also give people a sharper mind in old age.

Brassen dubbed the find "the positivity effect," a "biased tendency towards and preference for positive, emotionally gratifying experiences."

Participants both young and old were presented with pictures of happy, sad, fearful or neutral faces.

For those presented with happy faces, there was increased activity in the rostral anterior cingulate cortex, the part of the brain that controls emotions. Good mental health is associated with high levels of activity in this region of the brain.

"…When coping with extremely stressful life challenges, it is critical to appraise the situation realistically but also to approach it with a positive attitude," told ," Dr John Krystal, the editor of Biological Psychiatry, told the Telegraph.

The study is published in Biological Psychiatry.