Fig. 2.

Summary of raw data on social learning, absolute brain volume, group size, and longevity for 52 primate genera, using the consensus phylogeny from 10ktrees (65). For illustration purposes only, all data are summarized as genus-level means, standardized with minimum 0 and maximum 1. Also for illustration purposes only, social learning is displayed as a proportion of research effort whereas, in statistical analyses, social learning is controlled for research effort by including research effort as an independent variable. Images show (A) bearded capuchin (Cebus libidinosus), (B) chimpanzees (Pan troglodytes), and (C) guinea baboons (Papio papio), illustrating lineages that represent convergent coevolution of high social learning abilities, large brain volumes, complex social relationships, and long lifespans. (A) Courtesy of Flickr/Bart van Dorp, (B) courtesy of Flickr/USAID in Africa, and (C) courtesy of Flickr/William Warby.