Play, games, and the development of collective intentionality.

Play is a widespread phenomenon in the animal kingdom. But only humans engage in games, that is, in rule-governed, conventional play activities. We move pieces of wood on a board according to some arbitrary rules, making some of the pieces queens, others knights, and the whole activity that of chess. We walk on stages and declare war or peace—in games of makebelieve. No other species engages in such kinds of conventional rule and pretense games. Ontogenetically, human children from their second year on start to enter into such shared pretense and simple rule games. In fact, early pretend play and other games can be considered one of the core areas where