(Re-)conceptualisation in autism spectrum disorders
Burnett, Hollie G.
Thesis or dissertation
- © 2012 Hollie Burnett. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder.
Background: Individuals with Autism Spectrum Disorder (ASD) have been shown to be compromised in cognitive flexibility and attentional switching. However, most studies that examine these executive functions did not distinguish between the ability to form new concepts and the ability to switch between concepts. Very few attempts have been made to disassociate them as separate abilities, or investigate whether the animate or inanimate nature of the concepts/objects affects these abilities. Further, very few switching tasks have investigated the autistic spectrum as a whole, with most studies focusing on severely autistic individuals.
Aims: The aim of this thesis was to explore individual limitations in the perceptual-cognitive abilities of forming concepts (conceptualisation) and of switching between concepts (reconceptualisation) in individuals with varying degrees of ASD and in typically-developed (TD) individuals. Further aims were: (i) Examine whether the animate or inanimate nature of the concepts affect the (re-)conceptualisation abilities, and whether this effect varies along the autism spectrum. (ii) Examine the impact of the ‘salience of physical reality’ on the (re-)conceptualisation abilities. (iii) Examine whether there is a continuum in concept forming and/or switching underlying the entire autism spectrum, extending into the TD population.
Methods: The basic experimental paradigm involved recognition of ambiguous and impoverished objects. Distinct animate and/or inanimate objects were morphed into each other, resulting in a sequence of interpolations with decreasing proportions of one object and increasing proportions of the other object. Participants had to identify the newly emerging object. There were two distinct versions: the Conceptualisation Task, in which participants had to form a new concept from ‘scratch’, and the Reconceptualisation Task, in which an existing concept had to be traded in for a new concept.
Participants: Three different clinical groups were tested: adults with Asperger’s Syndrome (AS), children with AS, and children with autism. Each group and their control group, did not differ significantly in terms of age, sex or cognitive ability. In addition, on the basis of their score on the Autism Quotient (AQ), approximately the top and bottom 20% of the TD individuals were allocated to either a low or high AQ group.
Experiments: Four new experimental paradigms were employed: (Re-)Conceptualisation Silhouette Task (see Chapters 2 and 3), (Re-)conceptualisation Gabor Task (see Chapter 4), Delis-Kaplan Executive Functioning System (D-KEFS) Sorting Task with a unique added ‘No Shuffle’ condition, where the cards were not shuffled after each correct sort (see Chapter 5) and an Object-Ratio Task (see Chapter 7). In addition, the performance of the participant groups on these new tasks was compared with their performance on existing concept-switching tasks that are part of the D-KEFS: the Trail Making Task and the Twenty Questions Task (see Chapter 6).
Results: In both the Silhouette and Gabor tasks, the ASD groups were significantly impaired in identifying concepts compared to TD groups, in both the conceptualisation and the reconceptualisation conditions. However, the deficit was largest when they first had to disengage attention (reconceptualisation), and when the object was animate. The autism group performed worse than the AS group, but only with respect to animate objects. Furthermore, when the start-object remained physically present (Gabor Tasks), or when the correctly made sort was not shuffled, but remained physically present until a new sort was made (Card Sorting Task), the ASD groups were even more impaired. Quite strikingly, this impairment specifically pertained to animate objects. In the TD population, differences were found between those with low and those with high AQ scores. In terms of performance on the (Re-)Conceptualisation Tasks, the high AQ group occupied a position in between the low AQ and AS groups.
Conclusions: Overall, the studies suggest that individuals with ASD are impaired in forming new concepts, especially when they first have to disengage their attention from a previously identified concept, and when the concept is animate. This deficit also extends to the TD population (to those TD individuals with high AQ scores). The findings therefore support the notion of a concept forming and concept switching continuum, that is present not only in ASD, but also in the general population. The findings further suggest that individuals with ASD possess a processing deficit specifically for animate concepts/objects, which becomes worse with increasing ASD severity.
- Department of Psychology, The University of Hull
- Jellema, Tjeerd
- Sponsor (Organisation)
- Arts & Humanities Research Council (Great Britain)
- Qualification level
- Qualification name
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