Amazon calculates a product’s star ratings based on a machine learned model instead of a raw data average. The model takes into account factors including the age of a rating, whether the ratings are from verified purchasers, and factors that establish reviewer trustworthiness.
Well written and referenced, fairly balanced although always returning to the interesting underlying hypothesis that extended time in waterside environments near the Rift Valley of Africa selected for hominids with key adaptive features that helped the progression toward modern Homo sapiens. Artificial selection within populations, which also seems plausible, and similarly, the elimination of other tribe-equivalents, are not discussed. The book persuades me to read recent work by the master of human evolution, Desmond Morris.