title: Unsupervised categorization with individuals diagnosed as having moderate traumatic brain injury: Over-selective responding.
abstract: OBJECTIVE
  This study explored over-selectivity (executive dysfunction) using a standard unsupervised categorization task. Over-selectivity has been demonstrated using supervised categorization procedures (where training is given); however, little has been done in the way of unsupervised categorization (without training).
  
  
  METHODS
  A standard unsupervised categorization task was used to assess levels of over-selectivity in a traumatic brain injury (TBI) population. Individuals with TBI were selected from the Tertiary Traumatic Brain Injury Clinic at Swansea University and were asked to categorize two-dimensional items (pictures on cards), into groups that they felt were most intuitive, and without any learning (feedback from experimenter). This was compared against categories made by a control group for the same task.
  
  
  RESULTS
  The findings of this study demonstrate that individuals with TBI had deficits for both easy and difficult categorization sets, as indicated by a larger amount of one-dimensional sorting compared to control participants. Deficits were significantly greater for the easy condition.
  
  
  CONCLUSIONS
  The implications of these findings are discussed in the context of over-selectivity, and the processes that underlie this deficit. Also, the implications for using this procedure as a screening measure for over-selectivity in TBI are discussed.
authors.affiliation: a Swansea University , Swansea , Wales , UK.
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Edwards
authors.affiliation: a Swansea University , Swansea , Wales , UK.
authors.forename: Rodger
authors.initials: R
authors.lastname: Wood
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D000070642:Brain Injuries, Traumatic / Q000175:diagnosis / Q000523:psychology* / Q000534:rehabilitation*; D062309:Community Integration; D003210:Concept Formation / Q000502:physiology*; D006233:Persons with Disabilities / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D000072858:Psychosocial Support Systems; D012044:Regression Analysis; D020377:Self Efficacy; D012919:Social Behavior; D011795:Surveys and Questionnaires
keywords: Unsupervised categorization; cognition; over-selectivity; simplicity model; traumatic brain injury