The Yerkes-Dodson Law is a psychological principle that describes the relationship between arousal and performance. It suggests that there is an optimal level of arousal for peak performance; too little arousal can lead to underperformance, while too much can cause anxiety and hinder effectiveness. This creates a bell-shaped curve where moderate arousal leads to the best outcomes. The law was developed by psychologists Robert Yerkes and John D. Dodson in 1908. Their research indicated that the complexity of a task also influences the optimal arousal level. For simple tasks, higher arousal can enhance performance, while more complex tasks require lower arousal for better results.