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=James-Lange theory=

The James-Lange theory is one of the earliest theories of emotion and continues to inspire theory and research in cognitive science. Psychologists William James and Carl Lange published the theory at the same time in the 1890's, independently of one another. They believed that physiological changes in blood flow and muscle tension resulted in the feeling of emotions.

James and Lange proposed that certain stimuli or events can illicit arousal and physiological changes within the body. How an individual interprets such bodily responses results in the psychological manifestation of an emotion. According to this perspective, the sensation of bodily changes is a necessary condition of emotion and one would be unable to feel emotions without first interpreting responses from a perceived stimulus. Although both psychologists came to the conclusion that physiological changes precede the perception of emotions, their reasoning differed. James placed a greater emphasis on the viscera attributing to felt emotion whereas Lange attributed emotion to sensations from the vasomotor center. It would be reasonable to conclude that if these organic sensations were to be removed, no emotion would be felt.

Overview
In his original paper entitled “What is Emotion”, William James proposed the idea that bodily changes follow directly from the perception of an exciting stimulus. Our feelings of those changes as they occur produces emotion. Without bodily states changing following perception, emotions would be purely cognitive in form; pale, colourless, and destitute of emotional warmth. To draw an example from James, intuition says that if a person encounters a bear in the woods, that person becomes afraid and bodily changes ensue (i.e., he or she runs). James suggested the sequence was opposite; the perceptual stimulus of the bear produces an immediate motor reaction of fleeing, the sensory feedback of which generates emotional feelings. He argues that blood-vessels throughout the entire body, the bladder and bowels, the glands of the mouth, throat, and skin, and the liver are known to be affected in certain severe emotions, and are briefly affected when the emotions are of a lighter sort. He also added irregular heart-beat and breathing patterns, and muscle stiffness and tension as results of experiencing emotions. James states that each emotional experience is unique because they are accompanied by different variations of bodily changes.

The process for his theory can be summarized as follows: An object stimulates a sensory organ and afferent impulses pass to the cortex where the object is perceived. Currents are then passed down to the visceral where they are altered in complex ways. The impulses from these changed organs are then sent back to the cortex and are perceived as emotions. The feeling of bodily changes as they occur is the emotion being expressed. The main evidence supporting James’ theory is that because we are aware of tensions, throbs and pains, there would be nothing left if we took these feelings away and therefore no emotions would be felt. Imagine, feeling sad without tears; anger without muscle tension or heat in the face; and fear without a racing heart or an unsettled stomach. Therefore, it can be concluded that because bodily changes are necessary for the experience of feelings, they must also play a role in directly causing those feelings. . It should also be noted that James claimed that the theory could only be applied selectively to the relatively "pure" emotions such as grief, anger, fear and surprise.

Carl Lange had the same conception as William James but applied the theory more narrowly – on the changes of the circulatory system alone. Similar to James’, Lange agreed that if bodily changes did not give rise to feeling certain sensations (emotions), we would go through life unsympathetically and passionless. However, Lange argued that the stimulation of the vasomotor center was the principle route for causing emotions and affections.

Criticism
This theory was challenged in the 1920s by psychologist Walter Cannon and his student Philip Bard. Ironically, Cannon was an undergraduate student of James while he was studying at Harvard. Cannon and Bard developed a model of emotion (collectively known as the Cannon-Bard theory of emotion) theorizing that physiological changes and the feeling of emotions are independent of one another; arousal does not need to precede emotion. In his 1927 review of the James-Lange Theory, Cannon made a number of critiscisms to the reasoning behind the James-Lange theory. Some of his findings are as follows:


 * 1) Seperation of the viscera from the Central nervous system did not alter emotional behaviour. Sherrington and Cannon surgically removed organic sensations from the viscera and vasomotor system in animals.  Subsequent behaviour of the animals revealed no lessening of the intensity of emotional display.
 * 2) Viscera changes are too slow to be a source of emotional feeling  (i.e. - we 'feel' the emotion before the physiological changes have occurred).  Smooth muscle and glands respond with relative sluggishness (long latent periods) causing long delays before peripheral information reaches visceral structures.  In contrast to these long delays, observations have shown latent periods of affective reactions to photos of men and women to be much shorter.  In other words, emotions are being felt before bodily changes occur.
 * 3) The same visceral changes occur in very different emotional states and non-emotional states.  For example, visceral changes such as acceleration of the heart, increase in blood sugar and vasoconstriction are all associated with emotions such as fear and excitement, as well as with non-emotional states such as s fever and exposure to cold.  Furthermore, if emotions were the result of afferent impulses from the viscera, we should expect not only for fear and rage to feel alike, but chilliness, hypoglycemia, and fever should feel like them as well. Such is not the case.
 * 4) Artificial induction of adrenaline/epinephrine to induce the visceral changes typical of strong emotions does not produce emotions.  When adrenalin is injected directly into the blood stream or under the skin it induces bodily changes associated with emotion such as dilation of the bronchioles, constriction of blood vessels, increase in blood sugar levels, and stoppage of gastrointestinal functions.  Consistent with the James-Lange theory, if emotions are a consequence of the visceral changes, we should expect students who have received injections of adrenaline to experience emotions associated with the aforementioned bodily effects.  Results showed that students did not experience any specific emotions after being injected with adrenalin.

Two Factor Theory (Singer-Schacter Theory)
Stanley Schachter and Jerome Singer suggested that cognitive factors play a major role in determining emotion. They hypothesized that each individual interprets and labels the bodily changes they experience based on the situation they are in. Schachter and Singer’s theory is similar to that of James and Lange’s but expands more on the interpretation process. They argue that physiological arousal does not solely determine emotion; the context of the situation is also crucial. In other words, emotional state is a function of both physiological arousal and cognition. Cognitions from the current situation are influenced by past experiences and provide a framework for understanding and labeling one’s present feelings.

Schachter and Singer conducted a study that provided strong support for their theory. Two groups of participants were injected with epinephrine in order to induce physiological arousal. Each group was assigned to a room with two different confederates. The first group was assigned to a room where one of the confederates was acting very happy and silly with participants; the second group was assigned to a room where the confederate was quite angry and acting irritating. Afterwards, participants were asked to fill out questionnaires rating their experience with the confederates. The first group provided responses indicating feelings of happiness whereas the second group reported feeling angry and irritable. The results of this study indicate that arousal and the appraisal of the situation both determine how one interprets and labels their feelings.



Emergence Synthesis Approach
The most recent model of emotion formation incorporates elements from the James-Lange theory, Cannon-Bard theory, and Two Factor theory. The Emergence Synthesis approach is an integrative model that is currently the most favourable among psychologists. This theory argues that some type of emotions do not require any interpretation. In other words, they are triggered solely by an external stimulus. For example, it has been proven that fear is caused when a threatening stimulus activates a part of the brain called the amygdala. On the other hand, emotions such as guilt, are a combination of bodily changes, cognition, and knowledge from past experiences. Evidently, this modal supports the notion that several different pathways could influence the experience of emotion. They can be summarized as:
 * 1) Arousal;
 * 2) Cognition; or
 * 3) A combination of both arousal and cognition