This project uses a functional approach to understand how members of stigmatized groups perceive emotional expressions on others' faces. The project starts from the premise that different groups are seen to pose different threats to others, and thus different groups face prejudices colored by different, specific negative emotions. For example, prejudice toward Black men is driven largely by fear, whereas prejudice toward obese people is driven largely by disgust. Members of these groups may thus come to be "expert" in perceiving fear or disgust in others' faces, depending on the specific emotional prejudices others feel toward their group. Alternatively, members of these groups may be biased to over- or under-perceive these emotional expressions on others' faces. I used a functional approach to predict that, if a Black man believes that seeing others' fear expressions will be useful to him, he will tend to overperceive fear on others' faces, whereas if an obese man believes that seeing others' disgust expressions will be useful to him, he will tend to overperceive disgust on others' faces. If, however, it is not considered useful to perceive these prejudicial emotions on others' faces, Black men and obese people will tend to underperceive these emotional expressions. This study recruited Black men, overweight men, and a group of comparison men. All participants completed an emotion detection task in which they rated faces on whether they expressed fear, disgust, or no emotion. Participants were randomly assigned to complete this emotion detection task either before or after a questionnaire designed to make salient, as well as to measure, participants' beliefs about others' prejudices and stereotypes of their group. Finally, participants completed a set of measures tapping predicted moderator variables. Results suggested that a) Black men tend to be less sensitive perceivers of both fear and disgust on others' faces than are other groups, unless prejudice is salient, and b) variables that would guide the functionality of perceiving others' prejudicial emotional expressions (e.g., belief that prejudice toward one's group is justified, belief that group status differences are legitimate, belief that one can manage stigmatizing interactions, stigma consciousness, and emotion-specific metastereotypes of one's group) do predict differences among Black men in perceiving these emotions on others' faces. Most results for overweight participants were null findings. The results' implications for the psychology of detecting prejudice, and emotional expressions more broadly, are discussed.