Abstract: The Simon effect refers to the phenomenon in which responses are faster and more accurate when the stimulus location and the location of the assigned response correspond than when they do not. Researching this effect is important to understand perception-action relations. In the domain of Simon effect, most researchers thought that a common mechanism was involved in the Simon effect which was obtained under different experimental conditions. However, There is a growing number of evidence demonstrating that there were two different kinds of Simon effect, namely, Visuomotor Simon effect and Cognitive Simon effect. These two types of Simon effect could be affected by the stimulus form, arrangement mode, response rule and response manner. The Visuomotor Simon effect was due to the spatial code of a stimulus activating a congruent response, while the Cognitive Simon effect originated from the interaction between the code represented the stimulus position and the code represented the response position. The ventral stream and the dorsal stream were thought to be related with the Cognitive Simon effect and Visuomotor Simon effect, respectively.

Key words: Simon effect, response time distribution, lateralized readiness potential, visuomotor Simon effect, cognitive Simon effect