Book review: Sex at Dawn: The Prehistoric Origins of Modern Sexuality by Christopher Ryan and Cacilda Jetha.
This book makes a strong case that pre-agricultural humans were very far from monogamous, much like Chimps and Bonobos. It’s often convincing, but sometimes biased by ideology.
Some of the evidence comes from the difficulty that humans have being monogamous now, and the under-reported satisfaction of cultures that encourage egalitarian sharing of mates (including WWII pilots). Some stronger evidence comes from the size of our genitalia, and the promiscuous, egalitarian sex and reported absence of rape and war in our closest living relatives (Bonobos – have they really been observed well enough that we should expect to have seen rape and war?).
The book is highly critical of the Victorian version of marriage, but is somewhat approving of marriage as an institution if it’s more like some non-English cultures where occasional sex outside of the marriage is considered to be fairly harmless.
They also claim there was little violence, because food was abundant and it was normally easier to move to unoccupied land than to fight over resources. They provide decent reasons not to trust arguments that supposedly demonstrate high levels of violence in primitive cultures, but they don’t convince me they’re any more objective than the people they criticize. The most questionable part of this section is their belief that the natural growth rate of pre-agricultural humans was unusually low. They have some plausible reasons for expecting a slower population growth rate than the 25 year doubling time that Malthus expected in the absence of resource constraints, but they don’t come close to providing a good argument that Malthus was off by the factor of 10,000 that would be needed to reconcile the estimated pre-agricultural population growth rates with an absence of resource constraints. I get the impression that they imagine our direct ancestors had no competition from other hominids.
The book’s back flap claims that it contains an explanation of why homosexuality hasn’t been selected out of our genes, but the closest to that I could find in the book was a theory involving bonding which would explain bisexuality but not homosexuality.