Remembering the Past and Foreseeing the Future while Dealing with the Present: A Comparison of Young Adult and Elderly Cohorts on a Multitask Simulation of Occupational Activities

Abstract

Thirty-five young adult and 38 elderly cybernauts, matched for education, sex, alcohol consumption, and time/day of computer use were compared on a computerized simulation of professional activities of daily living (ADLs). The program quantified performance in terms of speed and accuracy on four major constructs: (1) planning (a 30-item office party script); (2) prospective memory (injections, sleep, phone); (3) working memory (PASAT, D2, and CES analogs); and (4) retrospective memory. Participants had to organize an office party, self inject insulin and go to bed at requisite times of day, do “office work” at unpredictable times of day, and answer the phone that blinked but did not ring (near threshold stimulus). The elderly were markedly and equally impaired on all four constructs (F = 24.3, p < .000). The elderly were also equally and markedly impaired on slave and central executive systems (c.f. Baddeley's model) and on event-based and time-based prospective memory (c.f. McDaniel's model)—findings arguing against a “frontal” model of cognitive decline. This supports Salthouse's concept of a “general factors” decline in normal aging due to diffuse deterioration of the brain. On the other hand, as expected from previous findings, the balance of omissiveness/commissiveness was significantly increased in the elderly sample's error profile. Furthermore, the balance of speed and accuracy was significantly increased in the elderly. This defines limits of the “general factors” model. The elderly also markedly underused a clock icon which had to be clicked on to get the virtual time of day necessary for integrating all the required actions. Prospective memory explained 11% of the aging variance despite partialing out of the three other constructs, making it appear as a golden standard of sensititivity to normal aging—though perhaps provided it be implemented in a distracting, multitask, strategically demanding context.

This research was made possible by a grant of the Fonds de Recherche en Santé du Québec accorded to Braun, Godbout, and Rouleau.

Notes

Note. The young and elderly participants did not differ significantly in the repartition of frequencies on either of the first two variables. A statistical comparison of the groups on the third variable would be meaningless. Education varied significantly as a function of occupation (F _{(4, 68)} = 3.56, p = .011).

¹English and French language versions of the experimental software used in this study are available upon request (for research collaboration). They require an IBM plateform equiped with any Windows software (its Visual Basic nodules not having been removed) and Excel.

∗The correction consists of a test not supposing equal within variances. Missing data were due to confusion of certain subjects (three young adults and five elderly) on the task making their performance ubiquitous. The most radical correction for type 1 error due to multiple comparisons (p/number of comparisons) would set alpha at .012.

Note. Age was dichotomized to eschew problems of meeting the assumption of linearity of the relation when one variable is markedly bimodal.