Perception, Cognition and Hetrogeneity in Autism Spectrum Disorder

Makhmood, Sonya. 2021. Perception, Cognition and Hetrogeneity in Autism Spectrum Disorder. Doctoral thesis, Goldsmiths, University of London [Thesis]

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Abstract or Description

Theoretical models of cognition in Autism Spectrum Disorder (ASD) propose that hierarchical processing is atypical and that perception is characterised by a local information processing bias. Whilst these models have gained considerable support from experimental studies, changes in ASD diagnostic criteria and increases in prevalence figures are reflected in increased heterogeneity at both cognitive and clinical levels in this condition. The aim of this study was to investigate perception and cognition in adolescents with ASD and typical development (TD) in the context of cognitive heterogeneity. Chapter two provided a detailed account of the standardised memory and intelligence tests administered in the study and the results from these tests were described in chapter three. Group differences, with poorer performance in the ASD group was observed on tests measuring verbal working memory, attention/concentration, whilst this group score higher on the Matrices subtest from the WASI-II (Wechsler, 2011). Inspection of individual data on standardised memory and intelligence tests revealed considerably variable subtest scores within the ASD group, and this was most marked on subtests measuring auditory and visual attention, visual perception, and memory for complex language. Experimental studies using flanker tasks to assess visual and auditory attention were presented in chapter four. The results from these studies showed some reduction in accuracy and an increase in RTs although responses to congruent and incongruent manipulations did not differ across groups. Experiment three, described in chapter five directly tested local and global processing using a Navon paradigm that included congruent and incongruent distractor trials. The group difference was marked on this study and showed a significantly increased susceptibility to both local and global incongruent distractors in the ASD group. The ASD scores on the selective attention and local/global processing tasks showed considerable within group variability and correlations carried out on the experimental and background data revealed links between task performance, cognitive and memory skills. In chapter six, a test of visual averaging was administered and failed to reveal a significant difference between the ASD and TD groups. These results were consistent with previous findings showing preserved visual averaging in adults with ASD. The results from the standardised and experimental tasks were discussed in chapter seven and it was concluded that the cognitive profile in ASD cannot be explained within a single theoretical model. Limitations in the studies and potential routes to better understanding heterogeneity in ASD were discussed.

Item Type:

Thesis (Doctoral)

Identification Number (DOI):


Autism, heterogeneity, cognition, perception, memory, intelligence, selective attention, local/global processing, cognitive model

Departments, Centres and Research Units:



31 December 2021

Item ID:


Date Deposited:

17 Jan 2022 16:14

Last Modified:

07 Sep 2022 17:19


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