lbeories in both the fields of ognstsvc aging and human neuropbychology have suggested that an impairment in the ability of an individual to inhibit irrelevant or distracting information either present in the environment or generated within the individual can ha‘ e detrimental effects on performance on a wide variety of cognitive tasks including text processing, inference formation, planning, and selective attention A number of researchers have attributed this increased distractibility in both clinical populations and health\ older individuals to a decline in or impairment of the functioning of the frontal lobes The present study extends findings suggesting a decline in frontal lobe function and increased susceptibility to distraction in healthy older individuals In addition, the possible relationship between these two phenomena is explored in a systematic fashion, an analysis absent in previous literature.
Individuals ranging in age from 20 to 80 years completed a battery of tests designed to appraise frontal lobe function (WCST, FAS Word Fluency Test, Cognitive Estimation Test, and Stroop Color/Word Test) and to determine the effects of distractors on task performance (Useful Field of View, Negative Priming Task). To equate for general verbal intelligence and short term memory span, individuals also completed the Ammons Quick IQ Test and the Digit Span Forward subtest of the WAIS-R.
Consistent with previous research, older individuals generally showed a decline in frontal lobe function as well as increased susceptibility to distraction when compared to the young individuals. The decline in frontal lobe function can be seen by increased repetitions and elaborations on the FAS, increased perseverative errors on the WCST, greater degrees of Stroop distraction and a decreased number of categories being obtained on the WCST, with age. Increased susceptibility to distraction is suggested by the impairment of many older individuals on UFOV task 3 and the distraction measure of the negative priming task. There was also a decline in negative priming with increasing age for some older individuals. However contrary to past research, several of the older individuals demonstrated negative priming effects equal to those found in the younger subjects. The expected relationship between frontal lobe function and susceptibility to distraction was found to be significant. UFOV task 3 shared approximately 1/3 of its variance with the frontal lobe composite measure.
The present study extends previous work suggesting that one function of the trontal lobes is to modulate the effects of irrelevant or distracting information on efficient cognition It also suggests that declines in inhibitory mechanisms, as assessed with the negative priming paradigm, can vary widely between older individuals.
| Identifer | oai:union.ndltd.org:WKU/oai:digitalcommons.wku.edu:theses-3969 |
| Date | 01 July 1993 |
| Creators | West, Robert |
| Publisher | TopSCHOLAR® |
| Source Sets | Western Kentucky University Theses |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Masters Theses & Specialist Projects |
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