The Typical and Atypical Development of Fine-grained Sensitivity to the Direction of Eye Gaze

Abstract

<p>Typical adults use gaze cues to make inferences about people's mental and emotional states. I investigated the development of fine-grained sensitivity to the direction of gaze during middle childhood, and how development differs in high-functioning adults with autism spectrum disorder (ASD). In Study 1, sensitivity to deviations of gaze from an object in the environment improved after age 6, becoming adult-like by age 10. This improvement may allow more precise inferences about others' interests and/or intentions. In Study 2, the horizontal range of directions of gaze perceived as direct (the cone of gaze) narrowed considerably after age 6, becoming adult-like by age 8. This narrowing may reduce social costs associated with erroneously perceiving direct gaze. In contrast, the vertical cone of gaze was adult-like at age 6. In Study 3, 6-year-olds' horizontal cone of gaze was narrower when they heard object-directed voice cues (e.g., “I see that.”) than when they heard participant-directed voice cues (e.g., “I see you.”) or no voice, a result suggesting that object-directed voice cues can allow more adult-like judgments of gaze. In Study 4, face inversion increased the width of the cone of gaze in typical adults, but not in those with ASD. However, the cone of gaze was normally modulated by facial expression in the ASD group. This pattern suggests that in adults with ASD, sensitivity to the direction of gaze is not tuned to be finer for upright faces, but that information is nevertheless integrated across expression and gaze. Together, these results suggest that although some aspects of sensitivity to the direction of gaze are adult-like at age 6, immaturities in other aspects of sensitivity will limit children's social judgments until at least age 8. The results also suggest that adults with ASD use atypical visual processing to discriminate the direction of gaze.</p>