In the we-knew-that-already department, a
has demonstrated that men prefer young women due to their
high fertility while women prefer older men due to their wealth and high
social status, which make them good providers for the offspring.
Well, duh.
More interesting is that the data suggest that men maximise
evolutionary fitness by marrying women 14.6 years their junior, and
women maximise their evolutionary fitness by marrying men
14.6 years their senior. That is, those couples had the highest
number of children reaching adulthood; the study spanned several
centuries of data and considered grand-children and I assume
great-grandchildren as well.
Even amongst primitive Lapplanders there’s a taboo against
large age differences, as in modern society, and thus most couples
didn’t have nearly as large an age difference. I suppose that
means that there’s even more competitive advantage for those
who did marry thus.
Given the notion that a man should marry a wife half his age plus
seven years (e.g. a man of 24 should marry a woman of 19), this would
indicate that a men should marry at 43 and women at 29 in order to
maximise evolutionary success. Seems a bit old for women, but it is
pretty obvious that a man of 43 is better-suited to providing for a
family than a younger man: he has managed to survive to 43, which is a
neat trick; he has probably socked away a great sum of money; less
likely to go off on wild-eyed crusades; more likely to have a strong
social network. And it doesn’t need noting that a woman of 29
is far, far, far more likely to have children than one of 43.