The volatile nature of positive affect effects: opposite effects of positive affect and time on task on proactive control.

There is growing evidence suggesting that positive affect promotes cognitive flexibility at the cost of increased distractibility and decreased proactive control. Regarding the latter effect, some studies revealed inconsistent or even diverging findings casting doubt on the reliability of this observation. Recently, it has been shown that motivation can counteract positive affect effects. Here, the authors provide evidence for another factor that opposes positive affect effects, namely time on and experience with a task. To this end, the well proven AX-continuous performance task (AX-CPT) was used. Three groups of participants received three blocks of the AX-CPT with a positive affect manipulation (positive group) or neutral affect manipulation (neutral group) or alternating affect blocks (mixed group: pos-neut-pos). Results confirmed the positive affect effect associated with decreased proactive control in the positive and mixed group as compared to the neutral group. Most importantly, all groups showed an increase in proactive control with increasing time on task supporting our prediction that time on task is another factor opposing the positive affect effect. The results thus reveal the sensitivity of the positive affect effect to strategic influences developed with increasing experience with the given task. Implications for future research on the interplay of mild positive affect and cognitive control will be discussed.