Ensemble perception in autism spectrum disorder: Member‐identification versus mean‐discrimination

Abstract

To efficiently represent the outside world our brain compresses sets of similar items into a summarized representation, a phenomenon known as ensemble perception. While most studies on ensemble perception investigate this perceptual mechanism in typically developing (TD) adults, more recently, researchers studying perceptual organization in individuals with autism spectrum disorder (ASD) have turned their attention toward ensemble perception. The current study is the first to investigate the use of ensemble perception for size in children with and without ASD (N = 42, 8-16 years). We administered a pair of tasks pioneered by Ariely [2001] evaluating both member-identification and mean-discrimination. In addition, we varied the distribution types of our sets to allow a more detailed evaluation of task performance. Results show that, overall, both groups performed similarly in the member-identification task, a test of "local perception," and similarly in the mean identification task, a test of "gist perception." However, in both tasks performance of the TD group was affected more strongly by the degree of stimulus variability in the set, than performance of the ASD group. These findings indicate that both TD children and children with ASD use ensemble statistics to represent a set of similar items, illustrating the fundamental nature of ensemble coding in visual perception. Differences in sensitivity to stimulus variability between both groups are discussed in relation to recent theories of information processing in ASD (e.g., increased sampling, decreased priors, increased precision). Autism Res 2017. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. Autism Res 2017, 10: 1291-1299. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

Relating the perception of visual ensemble statistics to individual levels of autistic traits

“…It should also be noted that our results here pertain directly to ensemble processing of the size of objects in an array, and these results may not generalize to ensemble processing of all types of stimulus features. Though these results are similar to previous findings of decreased ensemble processing of size, color, and facial identity (Corbett et al 2016;Maul et al, 2016;Rhodes et al, 2014;Van der Hallen et al, 2017), this decrease was not observed with ensemble processing of emotional expression (Karaminis et al, 2017) or with more homogeneous arrays (Van der Hallen et al, 2017). As such, future research incorporating multiple measures of ensemble processing across an array of stimulus features would be quite beneficial.…”

“…Individuals with ASD are able to represent some level of ensemble information, but this representation may be compromised when compared to TD individuals (Corbett, Venuti, & Melcher, 2016;Maul, Stanworth, Pellicano, & Franklin, 2016;Rhodes, Neumann, Ewing, & Palermo, 2014), though experimental variables such as ensemble heterogeneity may influence this effect (Van der Hallen et al, 2017). The results of the present study expand these latter findings to suggest that these findings are not constrained to individuals with a clinical diagnosis, but can also be observed in the general population relative to their individual level of autistic traits.…”

“…Participants were presented with an array of ten circles followed by a probe and asked if the probe was smaller or larger than the mean. Disrupted ensemble processing in ASD was observed when the distributions of sizes were highly heterogeneous (ten different dot sizes), but not when more homogeneous (two different dot sizes) ( Van der Hallen et al, 2017). With that said, individuals with ASD have demonstrated similar ensemble processing of arrays of emotional faces (Karaminis et al, 2017).…”

Perceptual effects of fast and automatic visual ensemble statistics from faces in individuals with typical development and autism spectrum conditions

“…It is also of interest to investigate this phenomenon in ASC since they are known to process human faces differentially 23,24 , with well-documented delays in the latency of N170 event-related potentials in response to faces 25 . Furthermore, while deficits have been found to occur, at least in low-level global summarizing abilities 26,27 , this has been contradicted 28 . Nonetheless, idiosyncrasies concerning ASCs' visual processing/perception and the possible implications of such perceptual biases regarding differences in visually guided cognition have been suggested 29 and atypical perception is included as a recent diagnostic criterion for ASC as per the Diagnostic and Statistical Manual of Mental Disorders (DSM)-V 30 .…”

Preservation of categorical perception for speech in autism with and without speech onset delay

“…Our results, showing no increased discrimination performance for within-category phonemic variants or for stimuli when presented as nonspeech stimuli, do not support this second account either. We should note here that in other domains, including the visual domain for which the first Bayesian accounts were proposed, evidence in favor of these two accounts is highly contradictory [e.g., Pell et al, 2016;Van der Hallen, Lemmens, Steyaert, Noens, & Wagemans, 2017]. A third account considers that prior knowledge once acquired will normally influence performance in perceptual task, but if the structure of perceptual information changes, people with autism have difficulties in accurately updating prior knowledge with the new perceptual regularities [Van de Cruys et al, 2014].…”