- 霊長類研究 (ISSN:09124047)
- vol.27, no.2, pp.127-139, 2011 (Released:2012-01-19)
Previous studies have used some verbs or nouns in ordinary language to describe, count, or analyze different types of animal behavior. However, the concept of "play" is problematic for ethological analysis. Although ethological analysis should be based on well-defined concepts, play is an ill-defined concept because the various meanings of the term necessarily make the boundary of the concept ambiguous and because the phenomena of play do not form discrete categories. Considering these difficulties, the ethological study of play should posit the argument that the concept of play is characterized by prototypeness. Consequently, the question "What is play?" is divided into the following three sub-types: (1) The question on our own cognition of play, "What type of phenomena do I (we) call play?"; (2) the question on the objective features of play, "What are the ethological features of the phenomena that we call play?"; and (3) the question on the animal cognition of play, "How do target animals recognize the phenomena that we call play?" By integrating prototype theory and the ethological study of play, we can establish various important and positive research agendas with respect to these three questions.