- After making an error, we usually slow down before our next response. This phenomenon is known as the posterror slowing (PES) effect. It has been interpreted to be an indicator of posterror behavioral adjustments and, therefore, has been linked to cognitive control. However, contradictory findings regarding PES and posterror accuracy cast doubt on such a relation. To determine whether behavior is adjusted after making an error, we investigated other features of behavior, such as the distribution of response times (RT) in a mental arithmetic task . Participants performed an arithmetic task with (Experiments 1 and 2) and without (Experiment 1) an accuracy-tracking procedure. On both tasks, participants responded more slowly and less accurately after errors. However, the RT distribution was more symmetrical on posterror trials compared to postcorrect trials, suggesting that a change in processing mode occurred after making an error, thus linking cognitive control to error monitoring, even in cases when accuracy decreased after errors. These findings expand our understanding on how posterror behavior is adjusted in mental arithmetic, and we propose that the measures of the RT distribution can be further used in other domains of error-monitoring research.