Positive and negative affects may bias behavior toward approach to rewards and withdrawal from threat, particularly when the contingencies are ambiguous. The hypothesis was that positive and negative affects would associate predictably with identification of happy, disgusted, or angry expressions that may signal potentially rewarding or aversive social interactions. Healthy volunteers (n=86) completed affect ratings and a facial emotion task that employed morphed continua in which emotional expressions gradually decreased in ambiguity. Relations between mood and intensity thresholds for emotion identification were computed. Anhedonia (low positive affect) predicted thresholds for happy expressions (r=0.24; P=.026) whereas negative affect predicted thresholds for disgust (r=-0.25; P=.022). Even within a normal range of mood, mood predicted emotion identification, supporting constructs of positive and negative affect derived originally from self-report measures.