Joint visual attention and social triangular engagement at 3 and 6 months.

Two experiments document infants' ability to detect breaks of contact in an ongoing dyadic interaction and to use the joint attention mechanism for social triangular communication purposes. In Experiment 1, the ability of 3- and 6-month-olds to show joint attention when an adult turned to face another person in sight, and to react when both adults conversed in a reciprocal manner, was measured. In Experiment 2, 3-month-olds were tested in two joint attention conditions: a Person-Person-Object condition (PPO) and a Person-Person-Person condition (PPP). Results showed that both 3- and 6-month-olds' gazed backwards and forwards between the two adults and produced socially directed behaviors towards the adults, thus initiating a social triangular coordinated interaction. Three-month-olds replicated this pattern in the PPP condition but not in the PPO condition. The social context with three persons may be particularly facilitative for infant early communication and sharing within the family.