Abstract
Previous work on visual differences in autism spectrum disorder (ASD) primarily focused on spatial processing, suggesting a local bias in ASD. Recently, Van der Hallen et al. (2015) argued for a shift from a spatial to temporal explanation for this; individuals with ASD may take longer to construct global representations. A useful measure of temporal processing is the Temporal Integration Window (TIW): if two events fall within the same TIW, they are integrated, if they fall in different TIWs, they are segmented (Blake & Lee, 2005; Wutz & Melcher, 2013). We measured TIWs in 18–36-month-old typically developing (TD) toddlers (N=57), toddlers with ASD (N=51), and adults (N=28) using a visual search, eye tracking task. Each trial consisted of a 4s sequence of two displays (ABAB…), each exposed for a stimulus-onset asynchrony (SOA) of 33,67,133, or 267ms. Each display contained a 4×4 virtual grid of distractors and one target. On integration trials, each display viewed alone has no visible target, but if integrated over time, a ‘pop-out’ target (that captures gaze) becomes visible. On segmentation trials, the target becomes visible when displays are perceived individually. Shorter SOAs, then, facilitate finding the integration target, while longer SOAs facilitate finding the segmentation target. The ‘crossover point’ where these two performance functions intersect provides the estimate of the TIW. Toddlers in both groups have longer TIWs (M=138.3ms) than adults (M=55ms), indicating that TIWs decrease with development. While TIWs in toddlers with ASD were longer than TD toddlers’ (ASD: M=151.2ms, TD: M=125.3ms), confidence intervals around the TIW estimates were large, meaning this difference was not significant. Analyses are ongoing, but this suggests that temporal processing, measured by the TIW, develops during early childhood but may not differ in ASD at this age.
Acknowledgement: This project was supported by a grant from the National Institute of Mental Health (R21MH117787)