Four-Factor Theory refers to one of the theories of emotions done by Parkinson (1994) which was subsequently developed by Eysenck in 1977. Four-Factor Theory of Emotion states that em otional experience depends of four(4) separate factors:
(1) Appraisal of some external stimulus or situation - the most important factor and also the one emphasized in the Lazarus Theory
(2) Reactions of the body, example is arousal which is the factor emphasized in the James-Lange theory.
(3) Facial expression- the importance of this factor was shown in the study by Strack, Martin, and Stepper (1988) in which participants were more amused by cartoons when adopting a facial expression close to a smile than when having an expression resembling a frown.
(4) Action tendencies - example is based on the theory of Frijda, Kuiper, and ter Schure, that is preparing to advance in a threatening way is associated with anger, whereas preparing to retreat is associated with fear.
According to this theory, these four (4) factors are not independent of each other. Cognitive appraisal of the situation affects bodily reactions, facial expressions, and action tendencies, as well as having a direct effect on emotional experience.