A forced-choice reaction time (RT) task was used to examine the relations between covert orienting (shifts of visual attention independent of eye movement) and filtering (the inhibition of processing of irrelevant stimuli) components of attention in persons with Down syndrome (n = 17) and children of average intelligence (n = 17) matched for mental age (MA), (MA = approximately 5 years). Conditions varied with regard to presence or absence of distractors, and the validity (valid, invalid, or neutral) of location cues. RT/p(correct) scores of both groups were longer in distractor-present conditions and in conditions when the location cue provided incorrect information (invalid cue). In addition, RT/p(correct) scores of both groups were longer when it was necessary to simultaneously search for a target and filter out irrelevant information, than when each of these attention demanding tasks was utilized separately. However, there were no differences in performance between persons with Down syndrome and MA matched children of average intelligence. This evidence is used to challenge the notion of an overall deficit in selective attention abilities in persons with Down syndrome as compared to MA matched children of average intelligence. Findings are also discussed in terms of their support for a capacity sharing relationship between covert orienting and filtering.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.68131 |
| Date | January 1994 |
| Creators | Randolph, Beth |
| Contributors | Burack, Jacob A. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Arts (Department of Educational and Counselling Psychology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001403969, proquestno: AAIMM94385, Theses scanned by UMI/ProQuest. |
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