Relating Infants' Social Engagement Profiles to Individual Differences in Language Outcomes

Abstract

Social engagement has been clearly associated with socio-developmental outcomes in clinical and at-risk populations of infants, who show deficits in gaze following, face processing, and joint attention. Importantly, these are all skills related to language learning. This is most prominently illustrated by individuals with autism, for whom social engagement and language are markedly dysfunctional. In contrast, for typically developing infants the parameters of social engagement and language learning have only been generally defined. The present study was designed to relate infants' social attention to later language outcomes. In this longitudinal study, 11-month-old infants participated in social attention tasks (distracter, gaze following and face scanning tasks); at 14 months, infants returned to participate in language (word/object association) and joint attention (Early Social Communication Scales) tasks; at 18-20 months, caregivers reported on language (vocabulary size) and autistic symptomatology (developmental screening measures). Overall, the results indicated that measures of social attention predict later language outcomes. In particular, joint attention accounted for 13% of the variance in infants' word/object association performance at 14-months. More frequent response to the joint attention bids of an adult female tester (e.g., looking in the direction of her pointing) was associated with better word/object association learning. With regard to vocabulary size, two tasks emerged as significant predictors, the distracter and joint attention tasks, which together accounted for 38% of the variance in language at 18-months. Specifically, longer latencies (i.e., less distractibility) to look away from the face when an adult female was speaking (distracter task) and more frequently responding to the attention bids of the tester were associated with a larger productive vocabulary size.