Affective influences abound in groups. In this article we propose an organizing model for understanding these affective influences and their effects on group life. We begin with individuallevel affective characteristics that members bring to their groups: moods, emotions, sentiments, and emotional intelligence. These affective characteristics then combine to form a group's affective composition. We discuss explicit and implicit processes through which this affective combination occurs by examining the research on emotional contagion, entrainment, modeling, and the manipulation of affect. We also explore how elements of the affective context, such as organizationwide emotion norms and the group's particular emotional history, may serve to constrain or amplify group members' emotions. The outcome, group emotion, results from the combination of the group's affective composition and the affective context in which the group is behaving. Last, we focus on the important interaction between nonaffective factors and affective factors in group life and suggest a possible agenda for future research. ᭧ 2001 Academic Press During the past century, a tremendous amount of research attention has been devoted to understanding the structure and performance of small groups (Levine & Moreland, 1990) . While it has been historically noted that groups possess both task and social/emotional components (Bales, 1950) , attention has primarily been directed toward understanding these tasks rather than emotional elements. This article is an attempt to delineate affective influences involved in group interaction and to explore the sharing of emotions among group members. We propose a dynamic organizing model of how affect operates in small groups. Through this model we discuss individual-level and contextual antecedents to group emotion, how the individual-level and contextual factors join together through emotional sharing processes to form group emotion, how group emotion influences group performance, and how group emotion feeds back into the group's affective system. The construct of group emotion and shared emotion among group members has been broadened in recent years. In much of early group research, if affective components were mentioned at all, it was in the context of individual-level satisfaction, morale, or cohesion. More recently, the social nature of emotions has been emphasized (Parkinson, 1996) , and affect has been explicitly recognized as an important stimulus in a group's environment (Hackman, 1992) . This recognition has increased as the construct of affect within groups, and in the workplace in general, has been expanded and reformulated, offering a more complete understanding of its role in small groups and organizations. While the concept of a group emotion has a long history, there is no one common definition. We define group emotion as the group's affective state that arises from the combination of its "bottom-up" components-affective compositional effects-and its "top-down" components-affective context (Barsade & Gibson, 1998) . That is, group emotion results from both the combinations of individual-level affective factors that group members possess as well as from group-or contextual-level factors that define or shape the affective experience of the group. The concept of group emotion has been shown to be reliably recognized by group members and outside raters, both on-site and through video ratings (Barsade, 2000; Bartel & Saavedra, 2000; Totterdell, Kellet, Teuchmann, & Briner, 1998) , and has been reliably measured through a variety of statistical techniques discussed later in the article. We specifically describe the posited processes behind these affective compositional and affective context effects and offer an organizing structure within which to examine these affective factors in small groups and work teams (see Fig. 1 ). The model we present suggests that affective influences in groups can be described in a general input, process, output form, where inputs refer to affective antecedents to the group experience, process refers to how affect is spread among other group members, and output refers to the resulting group emotion and its effects on group life. Following our organizing model, affective compositional effects begin with the variety of individual-level affective components members bring with them into the group interaction. We follow Ashforth and Humphrey (1995) in defining affect broadly and inclusively as a "subjective feeling state" that can range from diffuse moods to intense emotions. Group members bring their individuallevel emotional experiences, such as dispositional affect, moods, emotions, emotional intelligence, and sentiments, with them to a group interaction. We then suggest that through a variety of explicit and implicit processes, these affective inputs are communicated to other group members and form the affective compositional group effects. Explicitly conscious processes include various forms of socially induced affect, such as the deliberate creation or maintenance of emotional experience in group members through affective influence and what we term "affective impression management." Implicit processes include automatic affective transfer processes, such as emotional contagion, feeling affect vicariously, and behavioral entrainment, that lead to the spread of individual-level moods and emotions to other group members. Through these two types of emotional sharing processes, individual-level moods and emotions are spread and shared and form the "bottom-up" process of affective team composition (Barsade & Gibson, 1998) . We next discuss "top-down" factors in the group's affective context that may impose an affective tone on the group or amplify or constrain the ways in which a group experiences or expresses emotion. Specifically, we examine organizational emotion norms, local group norms, and the group's emotional history together as important context variables. We then suggest that the combination of the affective context and the group's affective composition leads to the group emotion at each given moment. Group emotion can refer to specific emotional states, such as group jealousy or envy, to more diffuse feeling states, such as pleasant or unpleasant group moods. The group emotion then feeds back into the affective antecedents and the affective context, leading to a dynamic affective system in the group. We have also included the presence of nonaffective context, processes, and outcomes in our model. It is beyond the scope of this article to discuss explicitly how affective and nonaffective variables interact, but by including them in the 102 KELLY AND BARSADE model we highlight that we expect a reciprocal relationship between affective and nonaffective factors. In the Discussion, we consider some areas of new research that examine how nonaffective context variables, such as intergroup relations, technology, and the physical context in which the group works, influence group emotion. There is a major conceptual question as to whether emotion, and the individual-level components that we outline in our model, can be meaningfully characterized at the group level. That is, what does it mean for a group to have an emotion? What is the most appropriate way to measure this group emotion? Our article seeks to answer these questions through the explanatory model it presents. Our premise is that while emotion is not a construct exclusive to groups, as is, for instance, "group size," it is sufficiently collective to merit consideration as a group-level construct. Specifically, we show that it has conceptual meaning at the group level of analysis as well as statistical evidence for its existence. As our model illustrates, we posit that it is the sharing processes leading to affective composition, and the mutual exposure to the affective context, which can explain how and why group emotion is viable and meaningful.
Previous research in the domain of work psychology has indicated that mood, emotion and team members empathy may influence team processes and the outcomes of teamwork, such as performance, cohesion and satisfaction REF .
Mood and Emotions in Small Groups and Work Teams
Organizational Behavior and Human Decision Processes
Psychology