title: Processing slow and fast motion in children with autism spectrum conditions.
abstract: Consistent with the dorsal stream hypothesis, difficulties processing dynamic information have previously been reported in individuals with autism spectrum conditions (ASC). However, no research has systematically compared motion processing abilities for slow and fast speeds. Here, we measured speed discrimination thresholds and motion coherence thresholds in slow (1.5 deg/sec) and fast (6 deg/sec) speed conditions in children with an ASC aged 7 to 14 years, and age- and ability-matched typically developing children. Unexpectedly, children with ASC were as sensitive as typically developing children to differences in speed at both slow and fast reference speeds. Yet, elevated motion coherence thresholds were found in children with ASC, but in the slow stimulus speed condition only. Rather than having pervasive difficulties in motion processing, as predicted by the dorsal stream hypothesis, these results suggest that children with ASC have a selective difficulty in extracting coherent motion information specifically at slow speeds. Understanding the effects of stimulus parameters such as stimulus speed will be important for resolving discrepancies between previous studies examining motion coherence thresholds in ASC and also for refining theoretical models of altered autistic perception.
authors.affiliation: Centre for Research in Autism and Education (CRAE), Department of Psychology and Human Development, Institute of Education, University of London, London.
authors.forename: Catherine
authors.initials: C
authors.lastname: Manning
authors.forename: Tony
authors.initials: T
authors.lastname: Charman
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Pellicano
mesh_terms: D000293:Adolescent; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000523:psychology*; D004056:Differential Threshold / Q000502:physiology; D004192:Discrimination, Psychological / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008606:Mental Processes / Q000502:physiology*; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods
keywords: autism; motion coherence; speed discrimination; visual motion processing