title: Age-related deficits in cognitive functioning are not mediated by time of day.
abstract: Few studies have examined whether cognitive performance of adults is influenced by the time of day in which they are tested. It has been suggested (May, Hasher, & Zacks, 1993) that some of the reported age differences in performance may be attenuated when older adults are tested during their optimal time, and younger adults are tested during their nonoptimal time. A total of 100 adults (20 to 78 years of age) participated in this study to investigate whether time of day and/or age are significant predictors of cognitive performance. Three tasks measuring crystallized and fluid types of abilities were employed. Hierarchical regression analyses revealed that age was a significant predictor for two of the tasks, whereas time of day of testing did not predict performance for any of the three types of tasks. The results suggest that time of day influences may be limited to specific types of cognitive abilities.
authors.affiliation: Department of Psychology, University of Calgary, 2500 University Drive N.W., Calgary, Alberta, T2N 1N4 Canada. lnbrown@ucalgary.ca
authors.forename: L N
authors.initials: LN
authors.lastname: Brown
authors.forename: K M
authors.initials: KM
authors.lastname: Goddard
authors.forename: C J
authors.initials: CJ
authors.lastname: Lahar
authors.forename: J L
authors.initials: JL
authors.lastname: Mosley
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000523:psychology*; D002940:Circadian Rhythm; D003071:Cognition; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged