Abstract
Humans rely on facial expressions to assess emotions in others. Of all the negative-valued emotions, pain remains the least accurately recognized, and this deficiency is even greater when the observer is a man (Wingenbach et al., 2018). Moreover, pain is often confused with emotions like anger and disgust (Kappesser & Williams, 2002). This study verifies whether patterns of similarity between mental representations of pain and other negative emotions vary as a function of the observer's sex. We first used the Reverse Correlation method (Mangini & Biederman, 2004) to reveal mental representations of pain facial expressions in 89 participants (42 males). We then presented all representations to a sample of 16 independent judges who rated how intensely they perceived the following emotions: anger, disgust, fear, happiness, sadness, surprise and pain. We calculated the average rating per emotion across the 16 judges for each of the 89 mental representations. A 2 (sex) by 7 (emotions) repeated measures ANOVA revealed a main effect of emotion (F(1,163.9)=167.1, p=<0.001), but no main effect of sex (p=0.75) or interaction was found (p=0.63). Post-hoc t-tests on each combination of emotions revealed significant differences in ratings of emotions except for disgust-anger and disgust-pain. We found anger and disgust rated as the most salient emotions, even more than pain. Lastly, a cluster analysis on the average ratings for each emotion (pooled across sexes) revealed 3 clusters, where the dominant emotion in the mental representation was 1) anger, 2) sadness and 3) anger and disgust equally. Our results suggest that emotions perceived in proxies of mental representations of pain extracted from men and women do not differ significantly. Interestingly however, our results reveal significant individual variations in the dominant emotions that are part of the mental representation of pain facial expressions.