Social decisions are heavily influenced by emotion. For decades, the dominant research paradigm has been characterized by a focus on the decision maker's own positive or negative mood. We argue that a full understanding of the role of emotion in social decision making requires a complementary focus on interpersonal effects (i.e., the effects of one individual's emotions on the other's behavior); a focus on discrete emotions rather than general mood states; and a distinction between cooperative and competitive settings. To advance insight into these issues we present the Emotions as Social Information (EASI) model. The model is grounded in two basic assumptions, namely that individuals use others' emotions to make sense of ambiguous situations, and that the effects of others' emotions and the processes that drive them depend critically on the cooperative or competitive nature of the situation. A review of recent research supports our analysis. We demonstrate that the interpersonal effects of emotions are pervasive and can be better understood in terms of the unique social functions of each emotion than in terms of valence. Effects in cooperative settings are best explained in terms of affective reactions (i.e., emotional contagion, affect infusion, and mood management), whereas effects in competitive contexts are better understood in terms of the strategic inferences individuals draw from other's emotions. We close by discussing the implications of our model and highlighting avenues for future research. Emotions have long been regarded as disruptive forces that interfere with rational decision making. Increasingly, however, this view has given way to a functional perspective on emotions. Contemporary scholars share the idea that emotions signal the importance of events to relevant concerns, help prioritize goals, and generate a state of action readiness that prepares the individual to respond to changes in the environment (see e.g., Frijda, 1986). This not only applies to individual goals and actions but also, and perhaps especially, to social interaction and decision making -situations in which one's own behavior influences and is influenced by one or more others. Indeed, social interactions are among the most commonly reported antecedents of emotions (Anderson & Guerrero, 1998;Shaver, Wu, & Schwartz, 1992), and emotions have plenty of potential to shape behavior (Frijda, 1986;Manstead, 1991;Van Kleef, 2009).Although the last decades have witnessed a growing attention to the role of emotion in social decision making, we believe that this research has not done justice to the inherently social nature of emotion. The reason is that most research has addressed the intrapersonal Emotions as Social Information 4 effects of affective states (especially positive vs. negative moods), demonstrating that individuals' judgments and decisions are influenced by their mood state (e.g., Ashby, Isen, & Turken, 1999;Forgas, 1995;Isen, 1987;Schwarz, Bless, & Bohner, 1991;Wyer, Clore, & Isbell, 1999). Although much of this ...