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The visual system must organize dynamic input into useful percepts across time, balancing between stability and sensitivity to change. The temporal integration window (TIW) has been hypothesized to underlie this balance: If two or more stimuli fall within the same TIW, they are integrated into a single percept; those that fall in different windows are segmented (Arnett & Di Lollo, 1979; Wutz, Muschter, van Koningsbruggen, Weisz, & Melcher, 2016). Visual TIWs have been studied in adults, showing average windows of 65 ms (Wutz et al., 2016); however, it is unclear how windows develop through early childhood. Here we measured TIWs in 5- to 7-year-old children and adults, using a variant of the missing dot task (Di Lollo, 1980; Wutz et al. 2016), in which integration and segmentation thresholds were measured within the same participant, using the same stimuli. Participants saw a sequence of two displays separated by an interstimulus interval (ISI) that determined the visibility of a visual search target. Longer ISIs increased the likelihood of detecting a segmentation target (but decreased detection for the integration target) although shorter ISIs increased the likelihood of detecting the integration target (but decreased detection of the segmentation target). We could then estimate the TIW by measuring the point at which these two functions intersect. Children's TIWs (M = 68 ms) were comparable to adults' (M = 73 ms) with no appreciable age trend within our sample, indicating that TIWs reach adult levels by approximately 5 years of age.

Individuals with autism spectrum disorder (ASD) experience differences in visual temporal processing, the part of vision responsible for parsing continuous input into discrete objects and events. Here we investigated temporal processing in 2‐year‐old toddlers diagnosed with ASD and age‐matched typically developing (TD) toddlers. We used a visual search task where the visibility of the target was determined by the pace of a display sequence. On integration trials, each display viewed alone had no visible target, but if integrated over time, the target became visible. On segmentation trials, the target became visible only when displays were perceptually segmented. We measured the percent of trials when participants fixated the target as a function of the stimulus onset asynchrony (SOA) between displays. We computed the crossover point of the integration and segmentation performance functions for each group, an estimate of the temporal integration window (TIW), the period in which visual input is combined. We found that both groups of toddlers had significantly longer TIWs (125 ms) than adults (65 ms) from previous studies using the same paradigm, and that toddlers with ASD had significantly shorter TIWs (108 ms) than chronologically age‐matched TD controls (142 ms). Lay Summary We investigated how young children, with and without autism, organize dynamic visual information across time, using a visual search paradigm. We found that toddlers with autism had higher temporal resolution than typically developing (TD) toddlers of the same age – that is, they are more likely to be able to detect rapid change across time, relative to TD toddlers. These differences in visual temporal processing can impact how one sees, interprets, and interacts with the world. Autism Res 2021, 14: 946–958. © 2020 International Society for Autism Research and Wiley Periodicals LLC.

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