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Effects of caffeine on prospective duration judgements of various intervals depend on task difficulty
Author(s) -
Gruber Ronald P.,
Block Richard A.
Publication year - 2005
Publication title -
human psychopharmacology: clinical and experimental
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.461
H-Index - 78
eISSN - 1099-1077
pISSN - 0885-6222
DOI - 10.1002/hup.687
Subject(s) - caffeine , psychology , placebo , duration (music) , task (project management) , time perception , audiology , cognitive psychology , physical medicine and rehabilitation , developmental psychology , cognition , neuroscience , medicine , psychiatry , art , alternative medicine , literature , management , pathology , economics
The effects of caffeine on prospective duration judgements were investigated in two double‐blind placebo‐controlled experiments. After taking either 200 mg of caffeine or a placebo, participants performed a task that demanded considerable attention, driving a car in a simulator (Experiment 1) or a task that demanded relatively little attention, watching a videotaped scene from a driven car (Experiment 2). Each participant made duration judgements of three target intervals: 15 s, 60 s and 300 s. Actively driving participants in the caffeine condition judged it as shorter than did those in the placebo condition. Caffeine had no effect on duration judgements following passive viewing. When people must perform a relatively difficult task, caffeine causes participants to allocate relatively more of their attentional resources to the task and relatively less to duration timing. Although caffeine may increase the pacemaker rate of an internal clock (via dopamine D 1 agonism), when external events are attention‐demanding, caffeine mainly influences the relative allocation of attention to external events or to time (via dopamine D 2 agonism) in cerebral areas subserving the executive control of attention. Copyright © 2005 John Wiley & Sons, Ltd.