||African American and White college students imagined interacting with a target person of either their own or a different race. During the imagined interaction, the target responded to them in either a friendly or an unfriendly way. The target's race had little influence on the accessibility of stereotype-related concepts in memory when his behavior confirmed expectations for members of one's own race to be friendly or members of a different race to be unfriendly. However, behavior that deviated from these expectations increased the accessibility of both concepts that were evaluatively consistent with a trait-based racial stereotype of the target and concepts that were inconsistent with this stereotype. When the target had been friendly, White participants judged him more favorably, and reported more positive affective reactions toward him, if he was African American than if he was White. When the target had been unfriendly, however, this difference was eliminated. White participants chose to sit closer to an African American confederate than to a White confederate regardless of the type of interaction they had imagined earlier, African American participants, however, did not. Results were consistent with the assumption that responses to social interactions are governed by situation stereotypes rather than by more general, trait-based stereotypes of the individuals involved in these interactions.