© 2017 by Annual Reviews. Human behavior is shaped by social learning to an extent that is unrivaled in the natural world. What neurobiological changes have occurred in human evolutionary history that have enabled this remarkable cultural capacity? Human brain anatomy and function have evolved to be highly responsive to experience from the environment, especially the milieu of social interactions. Numerous aspects of human brain development show evidence of specialization leading to increased plasticity. These include the timing of brain growth relative to birth, rates of synaptogenesis and myelination, and shifts in gene expression and epigenetic modifications. Some of these evolutionary changes in human brain plasticity are also evident in fossil hominins and from analyses of ancient DNA.