Von Hippel tells you in the intro that he wants to remove the tediousness of scientific writing by just assuming what he's saying is correct, and that really should have been my red flag to abandon ship.  However, plenty of pop culture writers have done an excellent job representing scientific data (I'm looking at you Carl Zimmer) so I kept going.

While there are some interesting studies discussed (very lightly and without much elaboration to the study design), there is a persistent thread of absenting the context of culture.  If socialization is the central component of human evolutionary "success" then it stands to reason that cultural context must be accounted for when studying human social behavior.

This book just isn't scientifically rigorous enough for someone with Von Hippel's pedigree, and I found myself constantly looking at the references and finding issues with his conclusions and subsequent narrative.  Statistics are, after all, what you make of them.