Valence, as used in psychology, especially in discussing emotions, means the intrinsic attractiveness (positive valence) or averseness (negative valence) of an event, object, or situation. However, the term is also used to characterize and categorize specific emotions. For example, the emotions popularly referred to as "negative", such as anger and fear, have "negative valence". Joy has "positive valence". Positively valenced emotions are evoked by positively valenced events, objects, or situations. The term is also used about the hedonic tone of feelings, affect, certain behaviors (for example, approach and avoidance), goal attainment or nonattainment, and conformity with or violation of norms. Ambivalence can be viewed as conflict between positive and negative valence-carriers.
Theorists taking a valence-based approach to studying affect, judgment, and choice posit that emotions with the same valence (i.e. anger and fear or pride and surprise) produce a similar influence on judgments and choices.
The term entered English usage in psychology with the translation from German ("Valenz") in 1935 of works of Kurt Lewin. Ambivalence has a longer history.
Valence is one criterion used in some definitions of emotion. The possible absence of valence is cited as a reason to exclude surprise from the list of emotions, though some would include it.
Valence could be assigned a number and treated as if it were measured, but the validity of a measurement based on a subjective report is questionable. Measurement based on observations of facial expressions, using the Facial Action Coding System and microexpressions (see Paul Ekman) or muscle activity detected through facial electromyography, or on modern functional brain imaging may overcome this objection.