Judging the intensity of facial expressions of emotion: depression-related biases in the processing of positive affect.

A forced-choice intensity judgment task was used to investigate biases in the processing of subtle expressions of emotion in participants with major depressive disorder (MDD). Participants were presented with 2 pictures of the same actor side by side, either depicting a neutral and a subtle emotional expression or depicting a subtle positive and a subtle negative expression. Participants were asked to indicate which of the 2 pictures showed the stronger emotion. Compared with participants with social anxiety disorder (SAD) and with never-disordered controls (CTLs), participants with MDD were less likely to judge subtle happy expressions as more intense than neutral expressions. In addition, compared with the CTL participants, participants who had MDD and participants who had SAD were less likely to judge subtle happy expressions to be more intense than negative expressions. Biases in the judgment of the intensity of subtle expressions of positive affect could play an important role in the interpersonal difficulties that are associated with depression.