Social Spectrum : understanding the incremental development of social skills in infants at-risk for autism

Autism Spectrum Disorder (ASD) is a neurological developmental disorder, characterized by difficulties with social communication and interactions. Social functioning varies within ASD as well as in neurotypical development (known as the Social Spectrum). This dissertation investigated the origins and incremental development of four social skills, and in particular, how social development differs across the Social Spectrum. This project assesses: 1) how four specific social skills develop independently and in relation to each other over time, and 2) the consequences of early social impairment on the development of these skills. Utilizing a longitudinal prospective study design, 40 infants at high- and low-risk of ASD (i.e., with or without a sibling with ASD) were evaluated at 12, 15, and 18 months, during a period when social skills are emerging and social impairment becomes apparent. First, individual skill development was evaluated over time and across the Social Spectrum using linear-mixed effects models. Results indicated that from 12 to 18 months: 1) certain joint attention skills are increasing over time, 2) social orienting skills varied across the Social Spectrum, and 3) development of certain response to distress reactions varied over time across the Social Spectrum. Secondly, the development of skills in relation to each other at each visit and over time was assessed, as well as how these interrelations differed based on the Social Spectrum. Key findings suggested that: 1) greater responding to joint attention is related to faster helping behaviors at and across 12 to 18 months, and 2) interrelations of the Social Spectrum, social orienting, and initiating joint attention at 15 months were related to helping at 18 months, such that greater social impairment and reduced initiating joint attention skills at 15 months were related to reduced social orienting at 15 months which was associated with slower latencies to offer help at 18 months. Investigating the incremental progression of social development and the diversion from development helps provides the target areas crucial for the early identification of and interventions for ASD.Psycholog