Quote · Modern Wisdom
The Uncomfortable Science Of Sex Differences - Steve Stewart-Williams - #1120
Where this was said
Are Human Sex Differences Unique?
At 56:13 · chapter starts 54:34
The discussion drifts into one of the episode's most affecting tangents: research showing that parental grief tracks the reproductive value of the child who has died — rising through childhood, peaking a couple of years after puberty, then declining. Stewart-Williams notes this has been replicated since Robert Wright first discussed it in The Moral Animal. The case of Darwin — who lost ten children, with the death of his 12-year-old daughter Annie being the most psychologically devastating — illustrates the pattern. Nobody is consciously calculating reproductive value when they grieve; the proximate emotion of devastating loss is real and complete in itself. But the underlying evolutionary logic, operating invisibly, shapes the intensity of that grief anyway. This segues into a broader defence of evolutionary psychology's framing of emotion: the proximate feeling and the ultimate explanation are separate questions, and confusing them is one of the most common misreadings of the field.
Only 5–10% of mammal species form pair bonds and share child-rearing. But roughly 90% of birds do. That puts humans squarely in the bird camp — and the implication is powerful: biparental investment is the primary reason human sex differences are more muted than in most mammals.
Only about 5–10% of mammal species form pair bonds and have biparental care, whereas roughly 90% of bird species do — making humans more like the average bird than the average mammal in their primary reproductive arrangement.
