The role of state and trait anxiety in the processing of facial expressions of emotion

State anxiety appears to influence facial emotion processing (Attwood of al. 2017 R. Soc. Open Sci. 4, 160855). We aimed to (i) replicate these findings and (ii) investigate the role of trait anxiety, in an experiment with healthy UK participants (N=48, 50% male, 50% high trait anxiety). High and low state anxiety were induced via inhalations of 7.5% carbon dioxide enriched air and medical air, respectively. High state anxiety reduced global emotion recognition accuracy (p =0.01, eta(2)(p) = 0.14), but it did not affect interpretation bias towards perceiving anger in ambiguous angry-happy facial morphs (p= 0.18, eta(2)(p) = 0.04). We found no clear evidence of a relationship between trait anxiety and global emotion recognition accuracy (p = 0.60, eta(2 )(p)= 0.01) or interpretation bias towards perceiving anger (p = 0.83, eta(2)(p) = 0.01). However, there was greater interpretation bias towards perceiving anger (i.e. away from happiness) during heightened state anxiety, among individuals with high trait anxiety (p =0.03, dz = 0.33). State anxiety appears to impair emotion recognition accuracy, and among individuals with high trait anxiety, it appears to increase biases towards perceiving anger (away from happiness). Trait anxiety alone does not appear to be associated with facial emotion processing.