MednickCaiKanadyDrummond08

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1 Comparing the beneﬁts of caffeine, naps and placebo on verbal, motor and perceptual memory

Comparing the beneﬁts of caffeine, naps and placebo on verbal, motor and perceptual memory

Mednick, Cai, Kanady & Drummond (2008). Comparing the beneﬁts of caffeine, naps and placebo on verbal, motor and perceptual memory. Behavioural Brain Research 193, 79–86
MednickCaiKanadyDrummond08.pdf

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Abstract

Caffeine, the world’s most common psychoactive substance, is used by approximately 90% of North Americans everyday. Little is known, however, about its beneﬁts for memory. Napping has been shown to increase alertness and promote learning on some memory tasks. We directly compared caffeine (200 mg) with napping (60–90 min) and placebo on three distinct memory processes: declarative verbal memory, procedural motor skills, and perceptual learning. In the verbal task, recall and recognition for unassociated words were tested after a 7 h retention period (with a between-session nap or drug intervention). A second, different, word list was administered post-intervention and memory was tested after a 20 min retention period. The non-declarative tasks (ﬁnger tapping task (FTT) and texture discrimination task (TDT)) were trained before the intervention and then retested afterwards. Naps enhanced recall of words after a 7 h and 20 min retention interval relative to both caffeine and placebo. Caffeine signiﬁcantly impaired motor learning compared to placebo and naps. Napping produced robust perceptual learning compared with placebo; however, naps and caffeine were not signiﬁcantly different. These ﬁndings provide evidence of the limited beneﬁts of caffeine for memory improvement compared with napping. We hypothesize that impairment from caffeine may be restricted to tasks that contain explicit information; whereas strictly implicit learning is less compromised.

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