As genome-wide association studies proceed, they are beginning to investigate human variation in cognitive and behavioral traits,39 and studies like these—such as the ones for height—will make it possible to explore whether the shift to behavioral modernity among our ancestors was driven by natural selection. This means that there is new hope for providing genetic insight into the mystery that puzzled Klein—the great change in human behavior suggested by the archaeological records of the Upper Paleolithic and Later Stone Age.
