What Is an Emotion?

Abstract To answer the question “What is an emotion?” theorists start from a descriptive definition that outlines the provisional boundaries around the set of phenomena commonly called emotions. They do this by listing typical and apparent properties of emotions—such as that they have mental and bodily aspects with a certain heat, automaticity, urgency, and irrational flavor—and/or by listing typical emotion types—such as anger, fear, sadness, and joy. Next, they seek explanations that provide a unique common ground for these phenomena (i.e., fruitfulness criterion), while also accounting for the listed properties and emotion types (i.e., similarity criterion). When successful, this approach leads to a scientific definition of emotions. Most psychological emotion theories achieve this by combining constitutive explanations (specifying the components of emotions) with causal-mechanistic explanations (specifying causal factors and mechanisms). The most consequential diversity within the emotion-theoretical landscape lies in their causal-mechanistic explanations, which can further be organized using three forks. The first fork separates personal from social theories; the second splits personal theories into behavior-oriented and feeling-oriented ones; and the third divides behavior-oriented theories into reactive and proactive ones. Reactive theories include evolutionary theories, network theories, and appraisal theories. Proactive theories are goal-directed theories. Feeling-oriented theories are psychological constructionist theories. Social theories can be seen as extensions of each of the other personal theories. The causal-mechanistic explanations offered by some of these theories have led to scientific definitions of emotions. Reactive theories define emotions as mental and physical changes caused by fixed cognition–motivation links: innate stimulus-response representations in evolutionary theories, learned stimulus-response representations in network theories, and abstract stimulus-response representations links in appraisal theories. Some psychological constructionist theories define emotions as emotion-specific feelings caused by the categorization of bodily feelings. While a strict application of these scientific definitions holds promise for fruitfulness, the heterogeneity of the descriptive set poses challenges to similarity with this set. To solve this tension, some theorists favor fruitfulness over similarity. They do this by trimming the set of emotions, splitting it, or eliminating it—as seen in some goal-directed and some psychological constructionist theories. Others favor similarity over fruitfulness by adopting a cluster-type definition.