Early Attention to Facial Expressions and Eye Gaze Direction in Infant Siblings of Children with Autism

Background: Social referencing behaviors typically develop between 9 and 12 months of age, and first instances of responding to joint attention (RJA) and initiating joint attention (IJA) begin emerging atop a foundation of referencing and gaze-following abilities shortly around this time. While it is known that the downstream cascade of gaze-related development is interrupted in children with autism, the earliest signs of this altered development in infancy are still poorly understood. Such understanding may be critical for early screening and treatment efforts. Objectives: To characterize visual fixation patterns to emotional faces with direct or averted gaze direction in infant siblings of children with autism (I-Sibs) across their first year. Methods: While undergoing infrared eye tracking, 25 I-Sibs at 6 and 12 months of age were presented a pseudo-randomized series of photographed faces depicting happy and angry expressions with either direct or averted gazes. Results: Overall attention to these faces at 6 months of age was disproportionately focused on the upper / eye regions, which was significantly more pronounced for direct-gaze happy faces. At 12 months of age, I-Sibs overall still preferred happy faces and direct gaze over angry faces and averted gaze. By this age, however, fixation of infants with higher developmental scores in expressive language and overall intelligence (as measured by the Mullen) was modulated by gaze direction and emotion type of the depicted face. Lower-performing infants preferred direct gaze in angry faces, whereas higher-performing infants preferred averted gaze in angry faces, and direct gaze in happy faces. Diagnostic outcome data will also be discussed, where available. Conclusions: Findings suggest that by 12 months of age, I-Sibs with higher language and cognitive abilities may discriminate differences in gaze and facial emotion to a greater degree than I-Sibs with lower language and cognitive abilities, and may adjust their visual attention accordingly. This is consistent with the literature of studies on early typically-developing infant looking preferences. We would expect I-Sibs who will go on to develop autism to achieve poorer early language and intelligence scores, and these individuals may also show coinciding impairments in the discrimination of and response to emotion and gaze cues early in infancy. Abnormally interpreting or responding to gaze and emotion cues as measured by visual fixation may offer easily-identified early risk factors for those infants within the first year of age who will subsequently be diagnosed with autism. Research supported by NIH/NIMH Autism Center for Excellence (ACE) center grant P50 HD055784.