1. Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
2. Interdepartmental Program in Anthropological Sciences, Stony Brook University, Stony Brook, NY 11794-4364, USA
3. Department of Psychology, University of Michigan, Ann Arbor, MI 48109-1043, USA
4. Department of Ecology and Evolution, University of Michigan, Ann Arbor, MI 48019-1085, USA
5. Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA
6. School of Life Sciences, Arizona State University, Tempe, AZ 85287-4701, USA
7. Center for Evolution and Medicine, Arizona State University, Tempe, AZ 85287-1701, USA
8. Department of Anthropology, University of Michigan, Ann Arbor, MI 48109-1107, USA