Story of Psychology - Morton Hunt [321]
For such reasons, the James-Lange theory survives—or at least is part of the contemporary understanding of the emotions. In recent decades, research by cognitive psychologists and by cognitive neuroscientists has yielded a complex, multifaceted explanation of the interaction between the physical symptoms of emotions and the neural processing of those symptoms and of the stimuli responsible. Which comes first, which produces the other? Each one, at times, depending on all sorts of conditions, and often both in a species of feedback. We will spare ourselves the intricacies for now; the net results suggest that both sides in the debate are right and that the neural systems of emotion and cognition are both independent and interdependent.28
In sum, the somatic theory is a valid but imperfect and limited part of the contemporary answer to the question about the sources of the emotions. Now let us go back to look at other theories explored during the last century that have contributed importantly to today’s view of the matter.
ANS and CNS Theory
Walter Cannon, whose experimental work called into question the James-Lange theory, offered his own theories of emotion and motivation; each was influential for many years.
His motivation theory—sometimes irreverently referred to as the spit-and-rumble theory—held that peripheral clues are what motivate a creature: a dry mouth will prompt drinking, a rumbling stomach will lead to eating. These clues, sending messages to the ancient part of the brain, there give rise to the drive to seek water or food.29 Ironically, Cannon was thus saying about motivation much the same thing he attacked in James’s theory of the emotions.
But Cannon’s theory of emotions was quite different. He held that peripheral or visceral conditions were not the cause of the emotions but concomitant effects of other causes. In gathering his evidence against the James-Lange theory, he decorticated some animals (removed their cortex), after which it took very little stimulus to elicit a rage reaction from them.
This led Cannon and a Harvard colleague, Philip Bard, to suggest that rage and other emotions originate in the thalamus, a primitive structure in the core of the brain that receives information from sense organs (except the nose) and relays appropriate messages to the cortex and the ANS. The cortex, according to the Cannon-Bard theory, usually controls and inhibits the thalamus, but when the thalamus sends it certain kinds of information—the sight of an enemy, for instance—the cortex relaxes its control. The thalamus then is able to send its emotional messages in two directions: to the nervous system, which produces the visceral responses of emotion and the appropriate behavior, and simultaneously back to the cortex, where the feeling of emotion is produced. Thus, the experience of emotion and its visceral symptoms are parallel effects of the thalamic messages.30
Of Cannon’s two theories, the spit-and-rumble account of drive, though dominant for some time, was eventually demolished by other experimental evidence. In 1939 two research studies used “sham drinking” to test it. A fistula surgically made in a dog’s esophagus drained off water as the dog drank, so that none reached the stomach. Although its mouth was wet, the dog continued drinking copiously without allaying its thirst. Evidently, nothing as simple as dry mouth caused the thirst drive; it came from other and deeper visceral signals, turned into action by the nervous system.
The Cannon-Bard emotion theory, however, was strongly supported, although modified, by later research showing that the ANS, thalamus, and other primitive areas of the nervous system could generate emotions without any input participation by the viscera. In the late 1920s and the 1930s Walter Hess, a Swiss physiologist, inserted electrodes in the rear area of the hypothalamus (a part of the core of the brain located below