Smiling, cooing, and "the game."

Two separate lines of my research with infants have recently merged in their implications for the meaning of smiling and cooing in early infancy. One line began as a study of the development of the perception of object orientation, and the other began as a study of early instrumental learning. Recently, data from these two research directions have suggested what might be called an ethological-social cognitive hypothesis concerning the onset of vigorous smiling and cooing in early infancy. This hypothesis is less simple than one might desire, but those who would focus on the limited parsimony rather than the presumed heuristic and explanatory breadth of this hypothesis will at least be pleased that it has been given a short name, "The Game."