psychology was fairly extensively remodeled by gene–culture coevolution. However, in ethnographically known societies, culturally transmitted norms and institutions do much heavy lifting. We do not anticipate finding that dramatic genetic changes were necessary to accompany the evolution of social complexity in the Holocene. The simpler societies known ethnographically rely heavily on norms and institutions to regulate social life, so no revolution in our innate psychology seems necessary to account for complex societies. Cosmides et al. (Chapter 15, this volume) suggest that much more of the load is carried by content-rich cognitive adaptations than by transmitted culture. Functional and developmental genomics should eventually lay a foundation for understanding the roles of genes and culture in current behavior and in the past evolution of current behavioral capacities.
Genomics has already made quite substantial contributions to our understanding of human evolution, beginning with the use of mitochondrial DNA variation to understand the timing of events in recent human evolution and to provide a window into human paleodemography, including past population sizes and migration patterns. The use of linkage disequilibrium to identify genes under recent selection suggests a massive Holocene wave of genetic change initiated by the cultural evolution of agricultural subsistence. Even here, our lack of knowledge of the functional significance of most of the alleles that have been under selection hides most of the details from us. As regards Plio-Pleistocene gene–culture coevolution, we are still at the very beginning of an understanding. In addition to a poor understanding of gene function, it is not clear how much information gene sequences contain about the timing of their selective history. Tools besides simple linkage disequilibrium suitable for deeper time will be required if genomics is to make a major contribution to resolving the many puzzles of the paleoanthropological record. We expect continued rapid progress.
Many thanks to Francisco Ayala and John Avise for organizing such an interesting conference and to our fellow presenters for enlightening papers and discussions.