Working memory efficacy and aging

Sanderson, Katherine Elizabeth (2006) Working memory efficacy and aging. Doctoral thesis, Northumbria University.

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Abstract

Abstract The aim of this thesis is to examine the effects of age on visuo-spatial sketchpad (VSSP) slave system processes and central executive working memory processes within the context of the multicomponent working memory model originally proposed by Baddeley & Hitch (1974). Previous cognitive aging research has tended to use general measures of working memory and little evidence has examined the effects of age specifically within the context of the multicomponent model. A series of seven studies was undertaken utilising a quasi-experimental design. Data was collected from convenience samples of young and old adults for each study, using a range of tasks and measures designed to make demands on VSSP and central executive processes. Effects of age were examined independently of speed of processing and intelligence by using these as covariates in the statistical analysis. Data was analysed using a series of ANOVA and ANCOVA analyses. Findings indicated that old adults were equivalent to young adults in their performance on the VSSP slave system tasks. However they showed an impaired performance on some measures of central executive processing, but not others. In particular, older adults showed a decline in the executive processes of task switching, which cannot be explained by speed of processing; whereas other putative executive processes, such as inhibitory processes, did not show an age-related decline. Results indicated that the age-related decline in task switching at the specific switch point is only evident when the demands for active memory processing are high. An age-related decline in the ability to co-ordinate the two tasks during task switching was also evident, and this age difference was not dependent on the active memory demands. These findings suggest that there are a number of separable executive processes, not all of which decline with age. The findings are discussed in relation to models of cognitive aging and theoretical models of working memory.

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