What is Play (activity)?
[[File:Soapbubbles-SteveEF.jpg|thumb|225px|[[Child]] playing with [[soap bubble|bubble]]s]] [[File:2006-07-09 katze2.jpg|thumb|225px|kitten at play]] '''Play''' is a word used in [[psychology]] and [[ethology]] to describe [[free will|voluntary]] activities associated with recreational pleasure and enjoyment,<ref name=Garvey>Garvey C. 1990. ''Play''. Cambridge, MA: Harvard University Press.</ref> and with early learning in [[mammals]]. Although everyone understands what the word means, it is extremely difficult to define.<ref>Reber, Aurthur S. & Emily S. 2001. ''The Penguin dictionary of psychology''. 3rd ed, Penguin Books, p543. {{ISBN|0-140-51451-1}}</ref> Play is usually connected with children and their juvenile-level activities, but it can also be a useful adult activity, and occurs among other higher-functioning animals as well. Many of the most prominent [[researcher]]s in the field of psychology (including [[William James]], [[Sigmund Freud]], [[Carl Jung]], [[Jean Piaget]] and [[Lev Vygotsky]]) have viewed play as [[endemic]] to the human species. Play may be frivolous; but it may be serious. A player can be intently focused on his or her objective (''[[flow (psychology)|in the zone]]''), particularly when play is structured and goal-oriented, as in a [[game]]. Accordingly, play can range from relaxed, free-spirited and spontaneous through frivolous to planned or even compulsive.<ref name=Huizinga>Huizinga J. 1955. ''Homo Ludens; a study of the play-element in culture''. Boston, Beacon Press</ref> == Function of play == There have been two major reviews of [[research]] into animal play, and both have said it is extremely difficult to define.<ref name=Fagan>Fagan, Robert 1981. ''Animal play behavior''. Oxford University Press. {{ISBN|0-19-502761-2}}</ref><ref name=Burgh>Burghardt, Gordon M. 2005. ''The genesis of animal play: testing the limits''. MIT Press. {{ISBN|978-0-262-52469-8}}</ref> Play is almost universal in very young mammals, and also in some groups of birds such as [[parrots]] and [[raven]