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Implicit cognition is impaired and dissociable in a head-injured group with executive deficits

Barker, L.A., Andrade, J., Romanowski, C.A.J., Morton, N. and Wasti, A. (2006) Implicit cognition is impaired and dissociable in a head-injured group with executive deficits. Neuropsychologia, 44 (8). pp. 1413-1424. ISSN 0028-3932


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Implicit or non-conscious cognition is traditionally assumed to be robust to pathology but Gomez-Beldarrain et al (1999, 2002) recently showed deficits on a single implicit task after head injury. Laboratory research suggests that implicit processes dissociate. This study therefore examined implicit cognition in 20 head-injured patients and age- and I.Q.-matched controls using a battery of four implicit cognition tasks: a Serial Reaction Time task (SRT), mere exposure effect task, automatic stereotype activation and hidden co-variation detection. Patients were assessed on an extensive neuropsychological battery, and MRI scanned. Inclusion criteria included impairment on at least one measure of executive function. The patient group was impaired relative to the control group on all the implicit cognition tasks except automatic stereotype activation. Effect size analyses using the control mean and standard deviation for reference showed further dissociations across patients and across implicit tasks. Patients impaired on implicit tasks had more cognitive deficits overall than those unimpaired, and a larger Dysexecutive Self/Other discrepancy (DEX) score suggesting greater behavioural problems. Performance on the SRT task correlated with a composite measure of executive function. Head-injury thus produced heterogeneous impairments in the implicit acquisition of new information. Implicit activation of existing knowledge structures appeared intact. Impairments in implicit cognition and executive function may interact to produce dysfunctional behaviour after head-injury. Future comparisons of implicit and explicit cognition should use several measures of each function, to ensure that they measure the latent variable of interest.

Item Type: Article
Copyright, Publisher and Additional Information: © 2005 Elsevier. This is an author produced version of an article published in Neuropsychologia. Uploaded in accordance with the publisher's self-archiving policy.
Keywords: Executive, social cognition, non-conscious processes, fractionated, head injury
Institution: The University of Sheffield
Academic Units: The University of Sheffield > Faculty of Science (Sheffield) > Department of Psychology (Sheffield)
Depositing User: Jackie Andrade
Date Deposited: 16 Jan 2006
Last Modified: 08 Feb 2013 16:57
Published Version: http://dx.doi.org/10.1016/j.neuropsychologia.2005....
Status: Published
Publisher: Elsevier
Refereed: Yes
Identification Number: 10.1016/j.neuropsychologia.2005.12.005
URI: http://eprints.whiterose.ac.uk/id/eprint/929

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