Mixed Messages is an extraordinary book, in my eyes perhaps the most important anthropological publication of its generation. It seeks to explain a wide variety of features of human societies in terms of a theory advanced by the evolutionary anthropologists Peter Richerson and Robert Boyd (2006), called dual inheritance theory. Dual inheritance theory posits that, with respect to humans, there are two parallel and independent evolutionary tracks, genetic and cultural. Not being cultural anthropologists, however, Richerson and Boyd offer a somewhat anemic account of the cultural side of this equation. Paul's book develops the cultural argument and in the process expands upon dual inheritance theory and adapts it to his task.

A crucial piece of Paul's argument rests on a growing consensus among evolutionary scholars that what accounts for the divergence of