The circumplex theory.
J. A. Russell and H. Schlosberg, in what is called the circumplex theory of emotion
, proposed that there are two essential dimensions (axes) of emotions, pleasantness versus misery and arousal versus sleepiness (Figure ). The names of various emotions, they suggested, could then be arranged in a circular fashion around these axes, with the placement indicating the relationship of emotions to one another. Excitement, for example, would lie in the quadrant bounded by arousal and pleasure, whereas distress would be in the quadrant bounded by misery and arousal.
Axes of Emotions
Tomkins's theory. Silvan Tomkins suggested that human emotions are of a limited number, genetically preprogrammed into the brain, and triggered by changes in stimulation. Changes in stimulation produce changes in patterns of neural firing that, in turn, cause changes in emotional experiences. According to Tomkins, emotion intensifies motivation and is necessary to instigate behavior. He proposed also that a preprogrammed set of facial‐muscle responses and vocalizations are associated with each emotion and allow the communication of emotional states.
Izard's theory. Carroll Izard identified ten primary emotions: fear, anger, shame, contempt, disgust, guilt, distress, interest, surprise, and joy—emotions that cannot be reduced to more basic emotions but that can be combined to produce other emotions. He further suggested that each emotion has its own neural basis and pattern of expression (usually denoted by facial expressions) and that each is experienced uniquely.
Plutchik's theory. Robert Plutchik argued for eight primary emotions, each directly related to an adaptive pattern of behavior necessary for survival. The eight emotions are anger, fear, sadness, disgust, surprise, expectancy, acceptance, and joy. Plutchik suggested that other emotions are variations of these eight and that emotions can complexly combine and can vary in intensity and persistence.
The opponent‐process theory. The opponent‐process theory, proposed by Richard Solomon and John Corbit, suggests that the experiencing of emotions disrupts the body's state of homeostasis and that emotions occur in basically opposite pairs—pleasure‐pain, depression‐elation, fear‐relief, and so forth—and oppose one another so that homeostasis can once again be achieved. The theory suggests that the experiencing of one emotion of a pair prompts the onset of the other emotion (the opponent process) as well, which eventually reduces the intensity of the first emotion and finally cancels it out. For example, although a rock climber may be terrified (an unpleasant emotion) in several climbs of a steep cliff, eventually, the thrill of safely reaching the top (a pleasant emotion) will cancel out that early fear. Some psychologists use this theory to explain drug addiction. The pleasure associated with taking an addictive drug is said to decrease over time because an opponent process is operating to reduce the pleasure. Consequently, more and more of the drug must be taken to achieve the original euphoric state and to avoid the pain of withdrawal.