Humans frequently encounter cognitive conflict situations, such as the need to ignore distractions or make a decision with multiple options. Cognitive control over attention and behavior in conflict situations is a basic executive functioning skill vital for goal-oriented behaviors. Musicians spend many hours exercising cognitive control while ignoring distractions, focusing on specific sounds, and avoiding incorrect movements. Therefore, musicians are a useful population to examine the effects of long-term experience on cognitive control. The current study used independent component analysis, time-frequency analysis, and ERP analysis on electrophysiological data to identify neocortical activity and timescales of cognitive control during an auditory Simon Task. Musicians showed no cognitive control advantage over non-musicians. Consistent with previous research, we found short-term compatibility sequence effects as well as longer-term effects of base rate (proportion of compatible trials) in response time Simon effect data. Sequence effects and a base rate x compatibility interaction also emerged for some ERP and ERSP components, including frontal theta in the ERSPs. We then used predictive models to test whether changes in the Simon effect across base rates were due to changing numbers of each sequence type that necessarily accompany base rate manipulations. Results indicate that sequence effects account for 17% of the reaction time cognitive control shift associated with proportion compatible manipulations. The base rate manipulation affected behavior and neural correlates above and beyond sequence effects. / Lisa Chinn