Nine-Month Revolution

Prior to nine months after birth, infants can only interact dyadically. That is, they can only recognize themselves and the object they are interacting with. All else is irrelevant to them and might as well not even exist. However, once this nine-month revolution occurs, it "result[s] in a referential triangle of child, adult, and the object or event with which they share attention" (The Cultural Origins of Human Cognition, 62). These "joint attentional interactions" start when the infants "begin to understand other persons as intentional agents like the self" (68).

Very fascinating stuff!