Mitchell P J, Redman J R
Department of Psychology, Monash University, Clayton, Victoria, Australia.
Psychopharmacology (Berl). 1992;109(1-2):121-6. doi: 10.1007/BF02245489.
The individual and interactive effects of caffeine, time of day and history of caffeine consumption on several study-related tasks were investigated in 25 subjects (6 males, 19 females). Performance was measured on short term memory (STM), mental arithmetic (MA), reading comprehension, serial search (SS) and verbal reasoning (VR). Subjects attended eight experimental sessions, at four times of day (0100, 0700, 1300 and 1900 hours), after ingesting caffeine (4 mg/kg) or placebo. Subjects were assigned to a low, moderate or high user group on the basis of a caffeine consumption questionnaire. Reading comprehension was affected by time of day, while caffeine improved performance on all mental speed-related tasks. High caffeine users performed more poorly than other groups on the verbal reasoning task. Several interactions between the three independent variables were observed on a number of tasks, supporting the contention that different processes underlying various types of cognitive performance are differentially, and often jointly, affected by caffeine, time of day and user history. Implications of caffeine usage on academic performance were discussed.
在25名受试者（6名男性，19名女性）中研究了咖啡因、一天中的时间以及咖啡因摄入史对几项与学习相关任务的个体和交互作用。对短期记忆（STM）、心算（MA）、阅读理解、序列搜索（SS）和言语推理（VR）进行了表现测量。受试者在一天中的四个时间点（01:00、07:00、13:00和19:00）摄入咖啡因（4mg/kg）或安慰剂后参加了八次实验。根据咖啡因消费问卷，受试者被分为低、中、高消费组。阅读理解受一天中时间的影响，而咖啡因提高了所有与心理速度相关任务的表现。高咖啡因消费者在言语推理任务上的表现比其他组更差。在一些任务上观察到了三个自变量之间的几种相互作用，支持了这样的观点，即各种认知表现背后的不同过程受到咖啡因、一天中的时间和消费者历史的不同影响，而且往往是共同影响。讨论了咖啡因使用对学业成绩的影响。
