Abstract
Cognitive control is the ability to monitor, evaluate, and adapt behavior in the service of long-term goals. Recent theories have proposed that the integral negative emotions elicited by conflict are critical for the adaptive adjustment of cognitive control. However, evidence for the negative valence of conflict in cognitive control tasks mainly comes from behavioral studies that interrupted trial sequences, making it difficult to directly test the link between conflict-induced affect and subsequent increases in cognitive control. In the present study, we therefore use online measures of valence-sensitive electromyography (EMG) of the facial corrugator (frowning) and zygomaticus (smiling) muscles while measuring the adaptive cognitive control in a Stroop-like task. In line with the prediction that conflict is aversive, results showed that conflict relative to non-conflict trials led to increased activity of the corrugator muscles after correct responses, both in a flanker task (Experiment 1) and in a prime-probe task (Experiment 2). This conflict-induced corrugator activity effect correlated marginally with conflict-driven increases in cognitive control in the next trial in the confound-minimalized task used in Experiment 2. However, in the absence of performance feedback (Experiment 3), no reliable effect of conflict was observed in the facial muscle activity despite robust behavioral conflict adaptation. Taken together, our results show that facial EMG can be used as an indirect index of the temporal dynamics of conflict-induced aversive signals and/or effortful processes in particular when performance feedback is presented, providing important new insights into the dynamic affective nature of cognitive control.