The Emotions as Social Information (EASI) model posits that emotional expressions exert interpersonal effects by triggering affective reactions and/or inferential processes in observers, depending on the observer’s information processing and the perceived appropriateness of the emotional expression. Since the EASI model was proposed, it has attracted extensive attention from researchers. Unfortunately, as a rising theory in recent ten years, the EASI model is still less studied in China. What are the unique theoretical contributions of the EASI model compared with other emotion theories? What progress has the EASI model made in recent ten years? What problems have been solved in various fields by using the EASI model? What other issues about the EASI model deserve further attention? To answer the above research questions, this paper discriminates the EASI model with other related theories, such as feelings-as-information theory, the dual-process model, the dual threshold model of anger, emotional contagion theory and affective event theory, to clarify the unique contributions of the EASI model in explaining emotion and related phenomena. Then, we searched and screened the empirical papers which clearly stated that they are based on the EASI model on Google Scholar, and found 63 papers in total. We review the application of the EASI model in the fields of leadership, team, customer service, negotiation and persuasion, and summarize the factors influencing the boundary conditions of the EASI model—the degree of information processing and perceived appropriateness based on the analysis of the 63 empirical papers using the EASI model. Overall, the inferential processes and affective reactions mechanism of the EASI model have been extensively verified in various fields. Among them, there are 33 studies in the field of leadership, 9 studies in the field of teamwork, 8 studies in the field of customer service, 8 studies in the field of negotiation, and 5 studies in the field of persuasion. There are mainly three factors influencing the degree of information processing: epistemic motivation (e.g., need for cognitive closure, personal need for structure, cognitive load), observer’s personality (e.g., implicit personality theory, conscientiousness, moral orientation, regulatory orientation, proactive personality) and employee’s efficiency. There are mainly four factors influencing perceived appropriateness: situational factors (e.g., emotional expression rules, culture, the relationship between the expressor and the observer), emotional expression content (e.g., intensity of the expression, authenticity of the expression, the target of the expression), expressor’s characteristics (e.g., leadership style, gender, race, power, status) and observer’s characteristics (e.g., agreeableness, regulatory orientation, power distance orientation, perceived leadership power). Based on the EASI model, we further integrate the existing research findings of the content structure, mediating mechanisms and boundary conditions of the social function of emotions into an integrated framework. Following our review, we identify avenues for future investigations. Future research should (1) strengthen the systematic verification of the EASI model, such as investigate both of the inferential processes and affective reactions as well as the observer’s information processing and perceived appropriateness at the same time, consider both of the reciprocal emotions and complementary emotions when investigate observer’s affective reactions; (2) enhance the integration of the EASI model with other theories (e.g., the dual threshold model of anger, emotion regulation theory, the adapted elaboration likelihood model); (3) extend the application context of the EASI model, specifically, future study can explore the mixed emotional expressions of one individual in multiple natural interaction situations, investigate the effect when the observer perceives different emotional expressions from different individuals at the same time, explore the possible effect when the observer perceives multiple emotional expressions changes of the same individual on related events at different time points, track the long-term social effect of emotional expressions, and explore the bystander effect of emotional expressions and the application of EASI in new organizational contexts; and (4) improve the measurement methods of inferential processes and affective reactions.
