Autonomic and attentional pathways in the emergence of autism: bridging mechanisms and real-world contexts in infancy.

Autism spectrum disorder (ASD) unfolds over the first two years of life through complex interactions among developmental systems. Attention and autonomic nervous system (ANS) regulation represent foundational processes critical for adaptive engagement with the environment. Disruptions in these systems during early infancy may initiate developmental cascades that contribute to core ASD features, including social-communication challenges and restricted and repetitive behaviors, as well as the vast heterogeneity found within ASD. This chapter reviews our approach to integrating mechanistic research and real-world methodologies to explore autonomic and attentional pathways in the early development of ASD. We conduct prospective, longitudinal studies to track how ANS regulation and attention unfold in infancy in infants at elevated and low familial likelihood for ASD. By integrating multimethod approaches to study these functions in naturalistic contexts, we demonstrate that autonomically regulated attention mechanisms support key developmental milestones and may play an important role in the emergence of ASD. Findings presented provide preliminary support for the theory that infants later diagnosed with ASD exhibit early disruptions in parasympathetic modulation of arousal and attention across responses to social and nonsocial contexts. This work emphasizes the value of leveraging portable, non-invasive technologies to study early autonomic and attention processes in naturalistic contexts. By using this approach to uncover formative mechanisms underlying ASD, we enhance the translational potential of this research while addressing critical gaps in inclusivity and representation. Understanding autonomic and attentional systems in infancy provides an opportunity to identify cascading developmental divergences and promote adaptive developmental trajectories in ASD.