AGE, INHIBITION, AND THE CONTENTS OF WORKING MEMORY

University Of Toronto, Toronto ON

Investigators

Linked publications & trials

Abstract

DESCRIPTION (adapted from investigator's abstract): The research explores age similarities and differences in control over thought and action on the assumption that basic attentional mechanisms that control the contents of working memory play a major role in determining high level cognition. The work evaluates a theoretical model (e.g., Hasher, Zacks & May, in press) that proposes that the critical attentional mechanisms involved in inhibiting irrelevant or no longer relevant thoughts and actions are, on average, less efficient in older than younger adults. Two broad issues are at the center of the present series of studies: (1) age related differences in inhibitory and possible similarities in noninhibitory control processes that determine the contents of working memory; (2) the consequences for retrieval of age differences in control over the momentary contents of working memory. Age differences in retrieval are expected to be larger for older adults than for younger adults because of reductions in inhibitory control over the contents of working memory. This will create more "cluttered" bundles of information in memory and the clutter, comprised of relevant target information, along with irrelevant distraction, will either decrease the chances of finding a target in memory or slow access greatly. Several experiments address these predictions and go beyond to establish the existence of organizational devices that can (a) reduce clutter and so (b) diminish the competition at retrieval between relevant and irrelevant information that is otherwise present for those with reduced inhibitory control over the contents of working memory. The use of such organizational devices should help to reduce memory lapses in older adults. Recent work suggests the existence of at least one noninhibitory process that may help to limit clutter in working memory: the semantic context in which individual words occur. It is possible, in contrast to some views of language processing, that meaning activation is quite narrow in natural language situations such as reading. The prediction pursued here is that younger and older adults will not differ in their ability to use this noninhibitory route to narrow meaning activation and so to control the contents of working memory. Findings from this line of work will help to establish boundary conditions for the role of inhibitory processes in controlling thought and action and they might help to foster the development of environmental conditions that would enable older adults to maintain high levels of cognitive functioning in their chosen environment.