The Yerkes-Dodson Law was developed by psychologists Robert M. Yerkes and John Dillingham Dodson in 1908. The law states that performance increases with physiological or mental arousal. There are two key components to the law which are the inverted-u arousal relationship and how the arousal interacts with task complexity. The inverted-u arousal is a concept that explains how performance can be influenced by arousal levels. This theory suggests that as arousal increases so does performance. It then levels off and then declines. When it comes to the task complexity, low arousal works best for difficult tasks and high arousal works best for easier tasks. Also, task performance is at its best when arousal levels are in the middle range between low arousal and high arousal. A lot of other psychologists came up with multiple other theories on why the level of performance on tasks changes with different levels of arousal. These would include the Hull-Spence theory and the Cusp Catastrophe Model Theory. Both were created by different psychologists but do explain a connection between levels of arousal and performance.