Affective variables have been shown to impact working memory and cognitive control. Theoretical arguments suggest that the functional impact of emotion on cognition might be mediated through shifting action dispositions related to changes in motivational orientation. The current study examined the effects of positive and negative affect on performance via direct manipulation of motivational state in tasks with high demands on cognitive control. Experiment 1 examined the effects of monetary reward on task-switching performance, while Experiment 2 examined the effects of (...) both rewards and punishments on working memory, using primary (liquid) reinforcers. In both experiments, dissociable trial-by-trial and contextual (block-related) enhancements of cognitive control during task performance were observed in relationship to motivational incentive value. Performance enhancements were equivalent in the reward and punishment conditions, but were differentially impacted by individual difference measures of trait reward and punishment sensitivity. Together, the results suggest both common and specific mechanisms by which approach and avoidance motivational states influence cognitive control, via activation of reward and punishment processing systems. (shrink)