Emotions are intense “stirred up” feelings, usually directed toward a specific person or event, and involving widespread visceral and skeletal changes.The feelings involved in emotion are extremely elusive and hard to describe. Any attempt at introspection tends to defeat itself since the intellectual attitude modifies or dispels the emotion being experienced. It is a well-known fact that when we closely observe ourselves during anger, we feel the emotion much less acutely. For this reason it has been said that such introspective experiments “die by their own description.”On the other hand, Nafe (1924) has found that milder affective states such as pleasant sensations produced by drawing fur gently across the neck could be adequately described without destroying the feeling in the process. The same was found for unpleasant stimulation, as in smelling glue or decayed flowers. Interestingly, both of these feeling states involve pressure sensations. When pleasure could be localized, it was felt most often as a bright, diffuse pressure in the neck and shoulder regions; unpleasantness appeared to be a dull or heavy pressure in the abdomen or lower trunk. It is probable that these pressure reactions are basically muscular in nature.The subjective descriptions of feelings and emotions have yielded very few concrete, verifiable results; and since the introspective method is no longer popular, psychologists have adopted more objective procedures. One technique is to note the overt changes that occur in different emotions—for example, speech changes due to the dry mouth experienced during stage fright, dilation of the pupils when we encounter a surprising or shocking scene, and the “drooping” posture of a person suffering from grief or depression. Other attempts to understand emotion through outward behavior are discussed under the topic EXPRESSIVE MOVEMENT.Another objective technique is to measure the internal, physiological changes that occur during emotion. Some of the major instruments used for this purpose are (a) the psychogalvanometer, a sensitive piece of apparatus which records involuntary changes in the electrical resistance of the skin (the galvanic skin response, or GSR) caused by sweating and possibly by muscular contractions occurring during intense emotion; (b) the electrocardiograph (EKG), which records the electrical activity of the heart—reliable in measuring the “pounding heart” that occurs in strong emotions, but unreliable for weak emotions; (c) the electroencephalograph (EEG), which generally shows a shift from the longer, slower Alpha- rhythms to shorter, more rapid “brain waves” under emotion; (d) the sphygmomanometer, used to measure blood- pressure changes in intense emotion; and (e) the polygraph, which measures the breathing pattern (inspiration/expiration ratio), blood pressure and GSR.The physiological basis of emotion was recognized by folklore and language long before scientists applied these instruments. The visceral areas are most often implicated, as in the expression “butterflies in the stomach,” the description of love as an “affair of the heart,” and the Scriptural assertion that the bowels are the seat of compassion. But the skeletal area is also involved: when we are tense, we are “tied in knots.” Although some of these expressions appear to localize the physiological changes, the current opinion is that they are extremely widespread and that there are more similarities than dissimilarities among the strong emotional states. In fact, physiologists and psychologists have all but despaired of finding exact patterns of physiological changes which differentiate the major emotions. Recently, however, there has been some evidence that anger is primarily controlled by epinephrine (adrenalin), which raises blood pressure by increasing the pumping of the heart; and that fear is the result of norepinephrine (noradrenalin) secretion, which raises blood pressure by constricting the blood vessels.Most of the physiological changes that take place during strong emotion are produced by the sympathetic nervous system. They generally have the effect of putting the organism on an emergency footing. Among the circulatory changes are: increase in heart rate; rise in blood pressure and pulse rate (though sometimes there may be a sudden and dangerous fall); constriction of the blood vessels in the gut, causing more blood to flow to the brain and muscle; increase in red corpuscles (making more oxygen available); rapid change of glycogen into blood sugar (releasing energy); and increase in blood-clotting time. The gastrointestinal and urinary changes include: reduced flow of saliva; inhibition of stomach movement, secretion of gastric juices, and peristalsis (slowing down digestion); inhibition of colon and bladder functions (often resulting in constipation) except in some cases of sudden stress, in which involuntary defecation and urination may occur.Other sympathetic effects are: increased sweating (to eliminate wastes and dissipate heat); goose pimples; gasping and panting under sudden stress, and deep breathing under prolonged exertion; dilation of the bronchioles (accelerating exchange of oxygen and carbon dioxide); dilation of pupils of the eye (apparently to see better). Glandular changes, primarily in the adrenals, also play an important role: adrenalin (epinephrine) reinforces the effects of the sympathetic nervous system; and norepinephrine contracts small blood vessels on the surface of the skin, which increases blood supply to the vital organs and also makes us look “white as a sheet.” In prolonged emotion the adrenal cortex is also stimulated, and this may eventually bring about psychosomatic effects such as hypertension.Finally, it is important to recognize that the physiological responses which occur under intense emotion may be either a help or a hindrance. A dry throat can keep us from speaking, or speaking clearly, just when we need our voice most. A “lump in the stomach” can be distracting and may also deplete our energy. Involuntary elimination can be embarrassing to a child and a danger to life on the battlefield. Muscles that become rigid in fright are worse than useless. On the other hand, by far the greatest number of changes that take place help us mobilize our energies and facilitate our handling of stressful situations. Perhaps the best evidence for this can be found in well- authenticated examples of people who perform astonishing feats under emotional circumstances—for example, the football player who plays a good part of a game with a dislocated knee, the frail mother who picks up the front end of her car to release her child pinned beneath it, the mountain climber who carries an injured companion down a treacherous slope during a raging snowstorm. In practically every one of these cases, the individual collapses when the ordeal is over, but emotion has carried him through. In most instances the emergencies are temporary and shortlived. As Hans Selye has pointed out, the human organism cannot remain overmobilized for extended periods without incurring tissue damage, especially to the vital internal organs.