Eyebrow angle and gaze direction as modulators of the emotional value of schematic faces: a visual mismatch response (vMMR) study (data)

Abstract

The aim of the present study was to examine if systematic manipulating with eyebrows and gaze directions expected to change the emotional value of schematic faces has an influence on the subjective and automatic discrimination of schematic faces and if this discrimination is influenced by the subjects’ emotional state. Participants (33 volunteers, 19-40 years, 17 females) took part in the vMMN experiment (optimal paradigm, non-face object with scrambled face features as a frequent standard and different types of rarely presented deviant stimuli – angry and neutral schematic faces with either modified eyebrow angles (0°, 19°, 38°), or gaze directions (left, right, direct). Subjective evaluations (valence, arousal and attracting attention) to the stimuli showed a clear gradience in the perceived emotional value for the angry and neutral faces based on their eyebrow angles, where a steeper (38° degree) angle meant being more negative in valence, more arousing and drawing more attention, suggesting that eyebrows play an important role in detecting emotions and their magnitude. Gaze direction proved to be a less determining feature, showing no differences between the directions for either the angry or neutral deviant. Based on the vMMN results we saw the main effect of emotion (neutral vs angry) for several electrode locations but manipulating with eyebrow angle or gaze direction did not yield in differences between the vMMN responses, showing that manipulating with facial features was not as effective on the brain level as it was for subjective evaluations, suggesting a more general categorization between angry and neutral emotions, regardless of the changes in low-level features. The subjects also evaluated their emotional state during the last month. The vMMN amplitudes were positively correlated with the anxiety and depressiveness subscale scores in some cases in the 141-160 ms interval and for both angry and neutral faces (Pearson r ranging from .42-.52), suggesting a possible connection between higher anxiety and depressiveness levels and smaller (i.e., more positive) vMMN amplitudes.