In a new study, psychologists found that a more mature brain is better equipped to see the sunny side of life.
As people move from middle to old age, they tend to focus on positive events and filter out bad ones, the researchers suggest.
Older people cope with a negative event by simply shrugging it off and moving on, said the study for the journal Perspectives on Psychological Science.
In contrast, younger people are more likely to dwell on a setback until something positive happens to distract them from it.
A series of tests showed older minds focus on the positive.
For example, after seeing a series of photos of faces, older people later recall the ones that are smiling.
This suggests that as the brain ages and loses some of its memory, there is a subconscious choice in what to remember and what to let go, and the positive memories are more likely to stay.
The researchers said: “Some psychologists believe that cognitive processes are responsible – in particular, focusing on and remembering positive events and leaving behind negative ones.
“Those processes, they think, help older people regulate their emotions, letting them view life in a sunnier light.”
The over-50s are also more likely than younger adults to “prune” their social circle or friends if they find any of their acquaintances ‘bring them down’.
Researcher Derek Isaacowitz of Northeastern University in Boston said more study was needed to help others by discovering why happiness and age were linked.
He added: “Older people are happier on average, but we still want to know in what situations does this particular strategy make this particular person with these particular qualities or strengths feel good.”