The rapid development of explicit gaze judgment ability at 3 years.

Two studies examined development of the ability to judge what another person is looking at. In Study 1, 54 2- to 4-year-olds judged where someone was looking in real-life, photograph, and drawing formats. A minority of 2-year-olds, but a majority of older children, passed all tasks, suggesting that the ability arises at around 3 years of age. Study 2 examined the fine-grained gaze judgment of 76 3- to 6-year-olds and 15 adults using gaze differences of 10 degrees and 15 degrees . Development of gaze judgment was gradual, from chance at 3 years of age to near adult-level performance at 6 years of age. Although performance was better when a congruent head turn was included, 3-year-olds were still at chance on 10 degrees head turn trials. The findings suggest that the ability to explicitly judge gaze is novel at 3 years of age and develops slowly thereafter. Therefore, the ability does not develop out of earlier gaze following. General implications for the evolution and development of gaze processing are discussed.