Abstract
Infants’ patterns of visual attention to faces change over the first two years of life. Typically developing (TD) infants tend to shift their attention from a speaker’s eyes to mouth, and this attentional shift has been shown to predict language outcomes. In contrast, infants later diagnosed with autism spectrum disorder (ASD) show atypical patterns of visual attention to faces, such as persistently reduced attention to a speaker’s eyes. However, the relationship between these visual fixation patterns and later language abilities is not well understood. This study examines the critical role of early visual attention in the acquisition and employment of functional language in a longitudinal cohort of infants at high and low familial risk for ASD. Eye-tracking measures of visual attention were collected and quantified as the percentage of time spent visually fixated on regions-of-interest (ROIs) defined as eyes, mouth, body, and object. At 24 months, language development was measured using the Mullen scales of early learning, and clinical best estimates confirmed diagnoses of ASD. Within-group Pearson correlations revealed that TD infants’ eye-looking at the beginning of the first year of life (n=93, Mage=5.14mo) positively predicted receptive language (r=0.312, p=0.002), and mouth-looking during the second year of life (n=80, Mage=15.21mo) trended towards positive prediction of expressive language scores. Increased visual attention to eyes at the beginning of the first year of life is therefore adaptive in TD infants. In infants later diagnosed with ASD, patterns of visual fixation were unrelated to language scores. Instead, ASD infants’ early eye-looking (n=40, Mage=5.12mo) and later (n=45, Mage=15.23mo) object-looking predicted ASD severity at 24 months (r=-0.346, p=0.029, r=0.384, p=0.009 respectively). Further analyses will investigate longitudinal trajectories of visual attention as predictors of language outcome in both ASD and TD infants.