Cognitive appraisal theory is a theory of emotions, which states that a person’s evaluative judgment (or appraisal) of a situation, event or object determines or contributes to his or her emotional response to it.
Cognitive appraisal theory is based on the James-Lange theory of emotions, but also takes into account that a given physiological response can give rise to various emotional responses.
The theory was originally proposed by American psychologist Stanley Schachter in 1964, and has later been developed further by other researchers. In an experiment carried out by Schachter and Singer, participants were injected with adrenaline, and not told that this would cause a heightened level of physiological arousal. When placed in situations designed to elicit either anger or euphoria, these subjects would attribute their state of arousal to the situation they were in.
Schachter, S. (1964) The interaction of cognitive and physiological determinants of emotional state, Advances in Experimental Social Psychology, pp. 49–79. New York: Academic Press.