Discuss three well-known three theories of human emotion.

The James-Lange Theory of
Emotion was developed in the nineteenth century by William James and Carl
Lange. They theorized that the automatic nervous system creates physiological events
like muscular tension, rise in heart rate, perspiration, and dryness of mouth which then
lead to an emotional response. A good example of this theory would be: a growling dog
(stimulus) leading to fast heart rate and breathing (perception of physiological
changes) which leads to fear or the idea of being afraid (identification of emotion).
This theory since has been disapproved by the field and challenged by others like Cannon
and Bard in the 1920’s but has not been further developed.

The
Cannon-Bard Theory of Emotion was developed in the
twentieth century by physiologists Walter Cannon and Philip Bard.  In contrast to the
James-Lange Theory, the Cannon-Bard Theory suggests that emotions occur simultaneously
with physiological responses.  In other words, an individual experiences an emotion and
the body immediately responds physiologically (i.e., muscular tension, perspiration,
increased heart-rate, etc.).  The Cannon-Bard Theory argues that emotions occur in
response to stimuli and are processed and responded to physiologically.  The James-Lange
Theory, on the other hand, suggests that the autonomic nervous system detects
physiological changes, thus leading to an emotional
response.

The Two-Factor Theory of Emotion
was developed by Stanley Schachter and Jerome Singer in 1962, and argues
that emotional states are impacted by both cognitive and physiological factors. 
According to this theory, physiological arousal causes people to search their
environment for "emotionally relevant cues" that explain their physiological
experience.  This allows a person to label their experience and associate it with a
particular emotional state.