Developmental Review 27 (2007) 261–276 www.elsevier.com/locate/dr 0273-2297/$ - see front matter  2006 Elsevier Inc. All rights reserved. doi:10.1016/j.dr.2006.09.001 Play in evolution and development  Anthony D. Pellegrini a,¤ , Danielle Dupuis a , Peter K. Smith b a Department of Educational Psychology, University of Minnesota, 214 Burton Hall, Minneapolis, MN 55455, USA b Goldsmith College, University of London, New cross, London SE14 6NW, UK Received 24 April 2006; revised 5 September 2006 Available online 17 October 2006 Abstract In this paper we examine the role of play in human ontogeny and phylogeny, following Surplus Resource Theory. We consider how juveniles use play to sample their environment in order to develop adaptive behaviors. We speculate about how innovative behaviors developed in play in response to environmental novelty may inXuence subsequent evolutionary processes. Play during this period of immaturity is especially important in the processes of development and evolution, because in play new strategies and behaviors can be developed with minimal costs and these strategies, in turn, can inXuence evolutionary processes. We posit that play inXuences these processes by support- ing the development of new strategies in novel environments during the juvenile period.  2006 Elsevier Inc. All rights reserved. Invoking evolutionary theories to explain the human condition has a long history in psychology. Darwin (1871, 1877) himself applied his theory of evolution by natural selec- tion to humans. Almost immediately this cause was taken up by others, for example Spen- cer (1878, 1898), in his book The Principles of Psychology. In the early 20th century, Hall (1904, 1916), the Wrst president of the American Psychological Association, also applied variants of this theory to human’s ontogenetic and phylogenetic development, perhaps most infamously hypothesizing, following Haeckel, that ontogeny recapitulates phylogeny. The importance of the roles of phylogeny and ontogeny in understanding human behavior  We acknowledge the comments of three anonymous reviewers as well as those of Marc BekoV, Dave Bjorklund, and Gordon Burghardt on various drafts of this paper. * Corresponding author. E-mail address: pelle013@umn.edu (A.D. Pellegrini).