Caffeine and Cognitive Performance: The Nonlinear Yerkes–Dodson Law
✍ Scribed by PAUL ANDREW WATTERS; FRANCES MARTIN; ZOLTAN SCHRETER
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 148 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0885-6222
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✦ Synopsis
This study presents a test of the Yerkes±Dodson Law (YDL; Yerkes and Dodson, 1908), which is understood to predict a negative quadratic relationship between arousal and performance (inverted-U' hypothesis), and a lower level of arousal for optimal performance on more dicult tasks than easier tasks (task diculty' hypothesis). A number of recent studies (e.g. Neiss, 1988) have questioned the validity of the YDL on several grounds: the confusion of theory and model; observed linear arousal±performance relationships; non-speci®c de®nitions of arousal; and poor experimental design. A single-blind modi®ed version of Anderson's (1994) within-subjects study (N 10) was performed, utilizing graded cortical arousal manipulations of caeine (100 mg cumulative dosages to a maximum of 600 mg), and four tests of basic cognitive ability in the procedural alphanumerical domain (with counterbalancing of drug/placebo session and ordering of presentations of tasks). The inverted-U' hypothesis was supported in three out of four experimental conditions (easy and dicult numerical, and dicult alphabetical tasks; p 0Á05). No support was found for the task diculty hypothesis. The results are discussed in terms of the emergence of nonlinearity in neural±cognitive interactions as a fundamental quality of drug±behaviour interactions.