This study tested the hypothesis derived from ecological theory that adaptive social perceptions of emotion expressions fuel trait impressions. Moreover, it was predicted that these impressions would be overgeneralized and perceived in faces that were not intentionally posing expressions but nevertheless varied in emotional demeanor. To test these predictions, perceivers viewed 32 untrained targets posing happy, surprised, angry, sad, and fearful expressions and formed impressions of their dominance and affiliation. When targets posed happiness and surprise they were perceived as high in dominance and affiliation whereas when they posed anger they were perceived as high in dominance and low in affiliation. When targets posed sadness and fear they were perceived as low in dominance. As predicted, many of these impressions were overgeneralized and attributed to targets who were not posing expressions. The observed effects were generally independent of the impact of other facial cues (i.e., attractiveness and babyishness).