In his intriguing account of a possible way in which human consciousness may have evolved, the philosopher Daniel Dennett has written:

I cite this evolutionary notion because I propose that children's play, with its repetitive and exploratory characteristics, represents not only fun but a critically important feature of their development of cognitive and emotional skills. Considering the various forms play takes, it is easy to identify the possible value of sensorimotor games for enhancing physical skills and even of games with rules for modeling early forms of orderly thought or even morality.

The value of pretending and of make-believe play seems less obvious; indeed, many parents are uncomfortable when they watch their toddlers or preschoolers pushing blocks and toy figures around while talking out loud to themselves.