Arousal and Valence Have Dissociable Effects on Responses to Schematic Emotional Faces

Studies examining behavioural responses to emotional stimuli usually report one of two patterns of responses to negative stimuli. Some studies find faster responses to negative material. Other studies find slower responses to negative stimuli. While the attentional mechanisms proposed to explain these findings (attentional capture in the former case, delayed disengagement in the latter) are not at odds with one another, the behavioural findings do need to be reconciled. We posit that arousal, being the primary differentiator of threatening and non-threatening stimuli, needs to be more carefully considered. To this end, two experiments were conducted evaluating the role of stimulus arousal and valence in the processing of schematic emotional faces. In experiment 1 stimulus arousal was manipulated via the presence or absence of eyebrows in the schematic faces in a faces flanker task. Results showed faster responses to faces with eyebrows but no differences in the faces flanker asymmetry between faces with and without eyebrows. In experiment 2, participants rated the faces on the evaluative space grid. Results showed the presence of the eyebrows had a greater impact on negative ratings for negative faces than for the other expressions. This suggests that stimulus valence and arousal were manipulated by the eyebrows and the reaction time differences could not be attributed purely to perceptual differences. Together these results suggests that both valence and arousal impact the processing of emotional schematic faces, and that these effects are dissociable.