Author's School

Graduate School of Arts & Sciences

Author's Department/Program



English (en)

Date of Award

January 2009

Degree Type


Degree Name

Doctor of Philosophy (PhD)

Chair and Committee

Sandra Hale


Prospective memory: ProM)-remembering to carry out intended actions at appropriate times-is a cognitive function that relies on controlled or automatic processing to various degrees. Age differences in ProM are most likely to be observed on tasks that rely heavily on controlled processes. This is consistent with certain frontal lobe theories of cognitive aging that also make predictions regarding age differences in performance variability on speeded components of ProM tasks that vary in the extent to which controlled processes are required. This study consisted of two experiments designed to test those predictions. In the first experiment, the degree to which controlled processes were necessary was manipulated by varying whether or not the ProM task focused processing on the cue. In the second experiment, this was achieved by varying the salience of the cue. The predictions tested in this study were that: 1) age differences in intraindividual variability of performance on certain aspects of ProM tasks exist and those differences are greater on tasks that encourage the engagement of controlled processing than on those that don't; and: 2) individual differences in intraindividual variability predict ProM performance and accounts for age differences in ProM performance. This was the first study to show that a ProM burden increases the skew of associated RT distributions. This was also the first study to clearly demonstrate that intraindividual variability, as indicated by the skew of RT distributions, is greater for older adults than for young adults. The test of the prediction that this age difference would increase as a function of the degree to which the ProM task required controlled processing was inconclusive. However, concordant with the predictions of frontal lobe theories, this study did find that the age difference in skew was larger when attention was divided than when it was not. This study was also successful in demonstrating the potential that measures of intraindividual variability have as predictors of ProM performance, although it was not possible to conclude that individual differences in intraindividual variability account for age differences in ProM performance.


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