Davidson R A, Smith B D
National Institutes of Health, NINDS, Bethesda, MD 20892.
Physiol Behav. 1991 Jun;49(6):1169-75. doi: 10.1016/0031-9384(91)90346-p.
Caffeine has been shown to affect both physiological functioning and certain aspects of performance. These effects are typically attributed to a simple increase in general arousal. The present study was based on the theory that the effects of caffeine are actually multidimensional. Specifically, we hypothesized that the drug raises arousal, acts to maintain elevated arousal under conditions otherwise conductive to habituation, and enhances the impact of situational and psychological sources of arousal. Subjects were given caffeine (300 mg) or placebo and white noise or no noise and exposed to a series of pure tones and two Backwards Recall Tasks, one novel, the other repetitive. Electrodermal activity (EDA) and task performance were recorded. Caffeine increased arousal as measured by EDA. It also acted to slow habituation during repetitive stimulation, thus maintaining heightened arousal. Finally, it enhanced the effects of novel stimulation, which also independently raised arousal. These results support a multidimensional theory of caffeine effects and provide some understanding of the popularity of caffeine as a psychotropic agent.
咖啡因已被证明会影响生理机能和某些方面的表现。这些影响通常归因于一般唤醒水平的简单提高。本研究基于这样一种理论，即咖啡因的作用实际上是多维度的。具体而言，我们假设该药物会提高唤醒水平，在其他有利于习惯化的条件下维持升高的唤醒水平，并增强情境和心理唤醒源的影响。给受试者服用咖啡因（300毫克）或安慰剂，同时给予白噪音或不给予噪音，并让他们接触一系列纯音和两项倒序回忆任务，一项是新颖的，另一项是重复性的。记录皮肤电活动（EDA）和任务表现。咖啡因如通过EDA测量的那样提高了唤醒水平。它还在重复刺激期间起到减缓习惯化的作用，从而维持较高的唤醒水平。最后，它增强了新颖刺激的效果，新颖刺激本身也会提高唤醒水平。这些结果支持了咖啡因作用的多维度理论，并为咖啡因作为一种精神药物的普及提供了一些理解。
