1. Correspondence: Department of Evolutionary Anthropology, Duke University, Durham, NC, United States;
2. Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, United States;
3. Department of Anthropology, University of Michigan, Ann Arbor, MI, USA;
4. Department of Psychology, University of Michigan, Ann Arbor, MI, USA;
5. College of Business, Stony Brook University, Stony Brook, NY, USA