A forced-choice reaction time (RT) task was used to examine the efficiency of visual filtering (the inhibition of processing of irrelevant stimuli) and the concomitant ability to narrow the focus of the attentional lens in persons with Down syndrome (n = 10) and children of average intelligence (n = 13) matched for mental age (MA) (average MA = approximately 5.7 years). Conditions varied with regard to the presence or absence of distractors and their proximity to a target stimulus, and the presence or absence of a visual window within which the target stimulus was presented. Although the study yielded no significant results due to a lack of power, the mean correct reaction times (RTs) indicate that both the adults with Down syndrome and the typically developing children were less efficient at filtering close distractors as compared to far distractors or no distractors. As well, the results suggest that the presence of the visual window failed to facilitate performance in both groups. Further investigation is warranted to determine the status of visual filtering in persons with Down syndrome relative to their level of functioning at an MA level of approximately 5 years, a period that is critical in the development of attentional processes.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.33903 |
| Date | January 2001 |
| Creators | Hitzig, Sander L. |
| 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: 001875939, proquestno: MQ79012, Theses scanned by UMI/ProQuest. |
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