Shared Norms and the Evolution of Ethnic Markers

Abstract
Department of Anthropology, University of California, Los Angeles, Calif. 90095, U. S. A., and Center for Adaptive Behavior and Cognition, Max Planck Institute for Human Development, Lentzeallee 94, 14195 Berlin, Germany (mcelreath@mpib. berlin. mpg. de) (McElreath)/Department of Anthropology, University of California, Los Angeles, Calif. 90095, U. S. A. (Boyd)/Department of Environmental Science and Policy, University of California, Davis, Calif. 95616, U. S. A. (Richerson). 15 III 02