Synonyms

Inverted-U function of arousal

Definition

This law states that a relationship between arousal and behavioral task performance exists, such that there is an optimal level of arousal for an optimal performance. Over- or under-arousal reduces task performance.

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Yerkes–Dodson Law. Figure 1

Historical Background

Yerkes and Dodson (1908) formulated their law to account for variance in habit formation based on the strength of stimuli used in conditioning paradigms. When stimuli were either too intense or lacked intensity, there was a drop in performance. This is characterized by inverted-U-shaped function, as shown here. Stimulus intensity was hypothesized to be a primary determinant of arousal, which was considered as the basis for this effect. Easterbrooke (1959) applied these principles to hypothesize that an increase in arousal leads to a decrease in the number of cues that can be utilized (cue-utilization hypothesis).

Current Knowledge

The inverted-U-shaped function between arousal and performance characterized by Yerkes and Dodson is very robust, such that in the behavioral sciences it is now considered as a law. The limitations of this function primarily are the by-product of ambiguity or disagreement over what constitutes arousal. Yet, there are numerous examples across various manifestations of arousal. For example, this principle is obvious when the relationship between the level of arousal and attentional performance is considered for the level of consciousness. People who are in a coma or deep sleep have limited responsiveness and are inattentive. Conversely, the agitation and hyperactivity that is often seen in cases of delirium also results in severe attentional impairments. When considered relative to anxiety, a similar relationship holds. A mild level of anxiety, which tends to be associated with a moderate level of arousal and motivation, usually does not hamper attentional performance, and often enhances it. However, as anxiety becomes excessive, the performance decreases. On the other hand, a complete lack of anxiety to the point of apathy tends to be associated with poor performance as well. This general relationship also holds for a variety of neurophysiological effects on attention, such as the effects of stimulant or sedative drugs.

A large research literature exists showing the performance differences as a function of levels of consciousness and arousal, and how these levels are associated with specific electroencephalography (EEG) bandwidths and other neurophysiological indices. There is also compelling evidence that the relationship between arousal and performance is strongly influenced by incentive, intrinsic motivation, task salience, and cognitive demand. Animals with very low and very high levels of cortisol, a stress response marker, show poorer learning and diminished survival when compared with animals with moderate cortisol levels, suggesting that the Yerkes–Dodson law has adaptive value.

Cross References

Arousal

Cue Dominance