LONGER LIVES may have led to civilization:

HUMAN lifespan took a sudden leap about 32,000 years ago, allowing people to grow older and wiser, scientists revealed yesterday.

The five-fold jump in longevity may have been the key factor that shaped modern civilisation. . . .

The American scientists believe there had to be a distinct evolutionary advantage to large numbers of people growing older.

On the one hand, it would have led to more disease and disability. On the other, it would have not only encouraged social relationships and kinship bonds, but also the passing of information from old and experienced individuals to younger generations.

Makes sense to me. You can’t build a civilization out of teenagers.

UPDATE: More here, including this observation: “Of course, ‘older’ in this context means making it to 30. Romanticized notions of prehistory obscure the fact that life back then was nasty, brutish and short.”