Prior affective and social knowledge about other individuals has been shown to modulate perception of their faces and gaze-related attentional processes. However, it remains unclear whether emotionally charged knowledge acquired through interactive social learning also modulates face processing and attentional control. Thus, the aim of this study was to test whether affective knowledge induced through social interactions in a naturalistic exchange game can influence early stages of face processing and attentional shifts in a subsequent gaze-cueing task. As indicated by self-reported ratings, the game was successful in inducing valenced affective knowledge towards positive and negative players. In the subsequent task, in which the locations of future targets were cued by the gaze of the game players, we observed enhanced early neural activity (larger amplitude of the P1 component) in response to a photograph of the negative player. This indicates that negative affective knowledge about an individual indeed modulates very early stages of the processing of this individual's face. Our study contributes to the existing literature by providing further evidence for the saliency of interactive social exchange paradigms that are used to induce affective knowledge. Moreover, it extends the previous research by presenting a very early modulation of perception by socially learned affective knowledge. Importantly, it also offers increased ecological validity of the findings due to the use of naturalistic social exchange in the study design.