Emotion

Emotion, term frequently and familiarly used as synonymous with feeling. In psychology it signifies a reaction involving certain physiological changes, such as an accelerated or retarded pulse rate, the diminished or increased activities of certain glands, or a change in body temperature, which stimulate the individual, or some component part of the individual's body, to further activity. The three primary reactions of this type are anger, love, and fear, which occur either as an immediate response to external stimuli or are the result of an indirect subjective process, such as memory, association, or introspection. The American psychologist John Watson proved in a series of experiments that infants are capable of these three emotions; he also demonstrated that emotional reactions may be conditioned.

The external stimuli diminish in importance, as a direct cause of the individual's emotional reaction, in proportion to the individual's maturity, and the stimuli that elicit these emotions develop more complexity. Thus, the same environmental condition that inspires anger in a child may cause fear in an adult. As the emotional degree of the reaction rises, however, the resemblance between the various kinds of reaction increases as well; thus, extreme anger, fear, or resentment have more in common than the same reactions in less exaggerated phases.

Momentary physiological change or distortion accompanies all emotional reactions, as in the instance of the accelerated heart action during a fit of anger. Fear, for example, may result in a violent physical manifestation such as the quaking of the limbs or a momentary loss of voice. It may also, by way of contrast, result in an attempt to disguise itself by means of an assumed coolness or bravado.