From the Inverted-U to the Extended-U: The Evolution of a Law of Psychology

Abstract

The Yerkes-Dodson relationship is one of the oldest 'laws' behavioral research. It is used repeatedly as an explanation for stress effects on performance and is a fixture of undergraduate psychological texts. However, as is the case of most classics, it is more cited than read. In actuality, Yerkes and Dodson's report dealt with animal learning under states of compulsion and is only tangentially related to human performance in stress filled conditions. Our re-evaluation is motivated by two primary circumstances. The first is the evident failure of the unitary arousal notion, which has commonly been invoked as the causal source to explain the Yerkes-Dodson, inverted-U relationship. The second relates to criticisms of the curvilinear description itself and its interpretations, which we present here. Together, these concerns demand not simply a re-evaluation, but a replacement of this over-simplistic and fundamentally flawed proposition. In repealing this 'law,' we offer a more sophisticated and hopefully more veridical representation, which is given primarily in the following reprinted article of Hancock and Warm (1989). This approach posits an 'extended-U' description founded upon attention and adaptability as central mechanisms of response.