How are Working Memory Capacity Measures, ‘Real-World’ Executive Performance and Midlife Aging Related?

Abstract

The aim of this study was to investigate the predictive value of measures of working memory capacity on executive performance within a real-world setting, and to assess the contribution of midlife aging to performance on both measures. Ten young adults (mean age 20.6 years) and ten middle-aged adults (mean age 45.4 years) completed an automated version of the Operation Span task as a test of working memory span. Participants also performed the Virtual Errands Task, a computerised test of multitasking ability similar to the Multiple Errands Task. All associations between Operation Span score and performance in the Virtual Errands Task were found to be non-significant, supporting the notion of working memory capacity being a more accurate measurement of the executive process of 'Updating' as opposed to being reflective of differences in overall frontal lobe functioning and central executive capability. Midlife aging was found to have a significant negative affect on performance on both tests. Regression indicated that midlife aging accounted for 32.4% and 35.6% of the variance on performance on the Operation Span and Virtual Errands Test respectively (p < 0.01 for both measures). Within the Virtual Errands Task, midlife aging was found to have a significant negative effect on realistic planning and task-switching ability. These results are interpreted in lieu of frontal lobe theories of aging, and suggest that cognitive decline in the studied executive processes’ neuroanatomical correlates occurs early in adult life.