Too Little, or Too Much
Beyond need-based accounts of motivation, arousal theories focus on how physiological and psychological AROUSAL LEVEL itself shapes behavior and performance. The classic finding here is the Yerkes-Dodson Law (1908): the relationship between arousal and performance follows an inverted U shape — performance is poor at very low arousal (under-aroused, unmotivated, sluggish), improves as arousal rises to a moderate, optimal level, and then DECLINES again if arousal becomes too high (overwhelmed, anxious, unable to focus).
Crucially, the Yerkes-Dodson Law also holds that the OPTIMAL level of arousal depends on task difficulty. For simple, well-practiced, or physically dominant tasks, higher arousal can continue to help performance further before it starts to hurt. For complex, unfamiliar, or cognitively demanding tasks, the optimal arousal level is LOWER, and performance starts declining sooner as arousal continues to rise — which is why a moderately nervous athlete might perform a well-drilled physical routine even better than usual, while the same level of nervous arousal can derail someone trying to solve a novel, tricky problem.
| Task type | Optimal arousal level |
|---|---|
| Simple / well-practiced | Relatively high |
| Complex / unfamiliar | Relatively low to moderate |
This inverted-U framework sits alongside other accounts of human needs and motivation discussed elsewhere in this course, like Maslow's hierarchy, but focuses specifically on the AROUSAL dimension: not just what a person needs, but how activated or "keyed up" they are while pursuing it, and how that activation level interacts with what the task actually demands.
Common pitfall: assuming "more arousal is always better for performance," or the reverse, "less arousal is always better." Both extremes are wrong under the Yerkes-Dodson Law — the relationship is curved, not linear, and the OPTIMAL point itself shifts depending on how difficult or complex the task is.
An inverted-U curve: a bare arousal-versus-performance axis; the curve for a simple task draws, peaking far to the right (high arousal); a second curve for a complex task draws in a contrasting shade.