Cause and effect: can positivity be taught?

"Over the hill". "Past your prime". There are plenty of cliches about ageing being all downhill.

But a long-term Yale study suggests the opposite may be true.

Researchers tracked thousands of adults over 65 for more than a decade, and found nearly half showed improved memory, cognition and walking speed — especially those with a positive attitude towards getting older.

Could a good dose of optimism help us age well?