Event-related potentials in the Simon task

In the Simon task, the reaction time to identify a target stimulus is slowed when the spatial location of target and its response coding do not correspond, compared with reaction times when spatial location and response coding do correspond. The present study examined the behavioral adjustment process in the Simon task using reaction time and ERPs. Behavioural results showed that the Simon effect included trial-to-trial behavioural adjustment process. ERPs on the early stage (N270 and P300 latency) showed the significant difference with S-R compatibility. However, no significant difference was observed in the N50-N150-ms range after responses.