机译:CURRENT PERSPECTIVES ON THE BIOLOGICAL STUDY OF PLAY:SIGNS OF PROGRESS
Department of Anthropology, Texas State University-San Marcos, San Marcos, Texas 78666 USA;
Departments of Psychology and Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee 37996 USA;
play behavior; adaptive function; hormones; neural mechanism; development; phylogeny; surplus resource theory; laughter;