Definition
The theories of emotion are the major scientific accounts of how emotional experience arises — what its causal sequence is, what role the body and the mind each play, and whether emotions are discrete, universal categories or constructed assemblies of more basic ingredients. The field is now more than a century old and has progressed through four principal positions, each of which corrected a perceived gap in its predecessor.
The earliest position, the James-Lange theory, held that the body reacts first and that emotional experience is the perception of that bodily reaction — we feel afraid because we tremble, not the other way round. The Cannon-Bard theory then argued that bodily and emotional responses occur in parallel rather than serially. The Schachter-Singer two-factor theory added that emotion requires both physiological arousal and a cognitive label that interprets the cause of the arousal. Modern appraisal theories and constructionist theories extend the cognitive element further, treating emotion as the product of how the situation is evaluated and how raw affect is parsed into culturally available categories.
Why it matters
How it works
James-Lange located emotion in the body: a stimulus produces a physiological response, and the perception of that response is what we call the emotion. Walter Cannon and Philip Bard objected that bodily responses are too slow and too undifferentiated to account for the speed and specificity of felt emotion — fear, anger, and disgust feel different but produce similar autonomic profiles — so they proposed that the thalamus simultaneously dispatches signals to the cortex to produce the felt experience and to the periphery to produce the bodily response. Schachter and Singer's classic adrenaline experiment then showed that participants who were physiologically aroused but uninformed about the source labeled their state according to the social context they were placed in, supporting the view that arousal alone is insufficient and that cognitive labeling completes the emotion.
Modern appraisal theory, developed by Richard Lazarus and his successors, treats emotion as the output of structured evaluations of the situation along dimensions such as goal relevance, agency, and coping potential. Different appraisal profiles produce different emotions: a setback judged to be one's own fault produces guilt; the same setback judged to be caused by another produces anger. Lisa Feldman Barrett's theory of constructed emotion pushes further, arguing that there are no biologically given emotion categories at all — only raw bodily affect that is parsed by the conceptual system into the emotion categories that one's culture has made available. The contemporary field weighs these positions empirically, with neuroimaging, cross-cultural data, and computational modeling each adjudicating between them in different ways.