The present study investigated the influence of emotional stimuli in the flanker task. In six experiments, separate influences of anticipating and reacting to valence-laden stimuli (affective pictures or facial expressions) on the flanker effect and its sequential modulation (also known as conflict adaptation) were examined. The results showed that there was little evidence that emotional stimuli influenced cognitive control when positive and negative stimuli appeared randomly during the flanker task. When positive and negative stimuli were separated between different participant groups in order to exclude a possible contamination from the effect of one valence to that of another, the sequential modulation was reduced when valence-laden stimuli were anticipated or had been presented on a preceding trial, regardless of the valence of the stimuli. A similar pattern was also obtained with facial expressions but only for response accuracy and only after valence-laden stimuli were presented on a preceding trial. The influences of anticipating and reacting to emotional stimuli were only partially replicated in the final two experiments where the arousal and valence of affective pictures were manipulated orthogonally. The lack of consistent influences of emotional stimuli on the flanker effect challenges the existing theories that implicate affective contributions to cognitive control.
Keywords: Dual-process framework; affect; arousal; conflict adaptation; valence.