Which statement best summarizes the Yerkes-Dodson law?

• A. Arousal improves performance regardless of task difficulty
• B. There is no relationship between arousal and performance
• C. There is an optimal level of arousal for performance; too little or too much impairs performance, and the optimal level depends on task difficulty
• D. High arousal is always best for all tasks

Answer: (C)

Performance rises with arousal up to a point, but too much or too little arousal will hurt performance. The Yerkes-Dodson law describes an inverted-U relationship: there is an optimal level of arousal that yields the best performance, and where that peak lies depends on how difficult the task is. For easy tasks, higher arousal can be beneficial up to that peak, while for difficult tasks, the optimal arousal is more moderate, and excessive arousal tends to impair performance by increasing anxiety or narrowing focus. So the best statement is the one that says there is an optimal arousal level for performance and that the optimal level varies with task difficulty.