The Story of Psychology
Page 69
But one can group all those theories into three categories: those that focus on the physical changes accompanying an emotion, such as increased heart rate, skin temperature, palmar sweating, and activation of areas of the brain; those that center on how an emotion feels—the subjective experience that we seek when we ask someone, “How are you feeling?”; and those that are concerned with what people believe or understand about why they feel as they do.10 The studies of the emotions throughout the twentieth century to the present essentially followed this very track: The early inquiries centered on somatic theory, the next group on ANS (autonomic nervous system) and CNS (central nervous system) aspects of emotions and motivation, and the third on the cognitive or thought processes involved.
All this may make emotion research sound remote from real life, and it is true that psychologists are interested in lofty questions about the emotions: what functions they serve, whether they are innate or acquired, whether they are universal or culturally variable, and how they are related to changes in the body and to mental processes. But psychologists are also interested in an eminently practical question: How are emotions related to behavior? Most of them agree that an emotion is not just a signal to the creature that some object or event is relevant to its needs; it is the means through which motivation becomes purposive action.11
Thus the ancient question—Why do we do what we do?—has become central to modern psychology, and the emotions are now seen as a crucial part of the answer. The study of emotion and motivation began with philosophic speculations, in the scientific era turned first to the investigation of physical needs, then to that of nervous system functions, later to that of cognitive processes, and finally to that of brain activation. It is a paradigm of the evolution of psychology itself.
Somatic Theory
What sort of person would starve a captive rat for two days, then put it in a box with a food pellet at the far end, which the rat cannot reach without scurrying across an electrically charged grid that shocks its feet? What sort of person would put a mother rat at one end of that box and her babies at the other?
A sadist, you might think. But Carl J. Warden was a very decent young man and not in the least sadistic; he was simply a typical experimental psychologist of the behaviorist era. The time was 1931, the place Columbia University, the apparatus his invention, the Columbia Obstruction Box, by means of which he was seeking to measure, as objectively as possible, the strength of two sources of motivation, the hunger drive and the maternal drive.
His data, he hoped, would validate the simple hypothesis that the greater the rat’s need, the greater its drive or motivation to allay that need. The measure of the need for food was simply how long the rat had been without any; the measure of the resulting drive was how frequently the rat would cross the electric grid for another morsel of food. The experiment proved Warden’s hypothesis correct up to the third day of deprivation; after that the rat became weakened and less driven to cross the grid. Motivation research could hardly have been more objective. (The trials with the mother and her babies yielded less satisfying results; the absence of the pups did not create as clear-cut a need as hunger.)12
In Warden’s report, as in other behaviorist writing, there was no talk of instinct. Behaviorists believed that almost everything a higher-order creature (like a mammal) does is the result of learning, and they viewed instinct theory as reactionary. By the 1920s they were calling the goal-directed energy of motivated behavior “drive” rather than instinct. Robert S. Woodworth, who proposed the concept of drive in 1918, said that although organisms possess innate mechanisms for such activities as seeking and devouring food, these lie idle until activated by a drive that directs the creature toward goals it has learned will allay the need. Behaviorists found drive a comfortable concept. Moreover, unlike instinct, it was one they could experimentally generate, measure, and modify by conditioning in the effort to determine the laws of motivation.
One of those hypotheses—a rather obvious one—was that the stronger a physiological need and the greater the drive to satisfy it, the more activity the creature will manifest. To test this hypothesis, in 1922 a Johns Hopkins University psychologist named Curt Richter mounted cages on springs and automatically recorded the movements of rats. Gratifyingly, the traces showed that hungry ones prowled around more than fed ones. In 1925 at the University of North Carolina, J. F. Dashiell used a checkerboard maze for the same purpose. He counted the number of squares rats entered and found that hungry ones explored more squares than fed ones. In 1931 Warden’s Columbia Obstruction Box was a still better method of measuring the same drive.
Throughout the 1920s and 1930s a good deal of such experimentation explored other primary drives, including those originating in the needs for fluids, oxygen, sex, a comfortable temperature, and the avoidance of pain. In 1943 these physiological aspects of motivation were merged in an elegantly simple theory by Clark Hull, the mathematical behaviorist, who asserted that all drives seek the same fundamental satisfaction—relief from the unpleasant tension created by a biological need—and that the ideal state sought by all creatures is the tranquillity that comes from the satisfaction of all drives.13 Nearly half a century later, ethological research would indeed show that many animals are torpid for a while when they have filled their bodily needs; a lion, after a big meal, may lie in the same spot for twelve hours at a stretch.14
But many forms of behavior do not fit within the borders of Hull’s theory. A dog will obey commands not to allay a biological need but to please its master; a hamster will run inside an exercise wheel for no apparent reason; a rat will learn to press a bar for a drop of saccharine-flavored water that has no nutritive value. To account for such behavior in accord with drive-reduction theory, behaviorists decided there were such things as “acquired” or “secondary” drives and motives. These arise from nonphysiological needs but gain their motive power by association with primary drives.15 The dog, for instance, learns to obey its master because at first it is rewarded by food and approval; eventually it develops a drive for approval, and approval becomes the reward.
Yet this jerry-built repair of drive theory could not account for some other kinds of behavior. It could not explain the hamster’s running or the rat’s working to get saccharine water. And unless “secondary drive” was defined so broadly as to include behavior not linked by conditioning to a physiological need, it could not explain why monkeys in one experiment pushed open a window again and again (it remained open only for thirty seconds) in order to watch a toy electric train running, or why monkeys in another experiment repeatedly unlatched a battery of hooks and latches even after they learned that doing so opened no doors and yielded no reward.16 Or why a music lover goes to a concert, a reformer labors to change the political system, a theologian strives to justify the ways of God to man, a penitent lashes his back with chains, a mountain climber scales the Matterhorn, or a psychologist investigates the phenomenon of motivation.
Hull’s idea that drive reduction is the goal of all motivated behavior was further challenged by a much-publicized experiment in sensory deprivation conducted at McGill University in 1957. Volunteers, wearing padded mitts and translucent goggles that admitted light but no images, spent several days lying on a soft foam-rubber pad in a small chamber where the monotonous hum of an air conditioner masked all other sounds. (They were allowed out briefly from time to time to eat, relieve themselves, and be tested.) Most of them had looked forward to a long, pleasant rest but soon found the absence of almost all sensory stimulation disagreeable and disorienting. They had difficulty thinking coherently, their moods fluctuated between hilarity and irritability, their performance on standard tests of mental ability deteriorated markedly, a few of them experienced hallucinations, and nearly all asked to be released from the experiment after a few days.17
Clearly, many kinds of behavior are motivated by complex needs generated by the autonomic and central nervous systems and the mind; this was what emotion and motivation researc
hers had been ignoring.
Over the years, however, as researchers explored the complexities of conflicting motivations that could not all be accounted for by internal drives or needs, they recognized that some behavior is motivated by “incentives”—external stimuli or rewards not directly related to biological needs. Many people will stay up late watching a movie although they need, and know they need, to go to sleep; many will keep nibbling canapés at a party to be social, even though they feel overfull. Eventually, in 1989 and 2001, the British psychologist Michael Apter advanced a “reversal theory” of “metamotivation”: We can switch from one motivational state to its equally rewarding opposite, but can never be in a state where both pertain. For instance, we are in an achievement oriented motivational state when working on some important project, but may at some point reverse to an enjoyment-motivated state to take a break and have a snack; both states gratify needs but in opposite ways. Apter’s team asked parachute jumpers about their feelings just before and after jumping: In both conditions the reward was one of great arousal, but before jumping the arousal was due to great anxiety, afterward to great pleasure.18
But now we must get back to our story.
Although behaviorists could observe and measure the external activities associated with motivation, they could neither observe nor measure physical indices of emotion. A rat could not tell them what it was feeling, and though a human being could, they regarded such information as unverifiable and scientifically valueless.
Not all psychologists, however, felt bound by the behaviorist prescription for acceptable evidence; some were willing to accept a human being’s identification of what he or she was feeling. But even they, during the early decades of the century, were interested chiefly in the physiological changes accompanying the emotions the subjects said they felt and which, the researchers believed, were the source of those emotions.
This theory, as we saw earlier, had been advanced by William James in 1884 and almost simultaneously by Carl Lange, a Danish physiologist. The James-Lange theory held that—contrary to our impression that some fact excites an emotion in us and this gives rise to bodily changes—an exciting fact brings about bodily changes, and our perception of those changes is the emotion. (As James put it, we meet a bear and tremble, and because we tremble feel afraid.)
The James-Lange theory was generally accepted for many years, and by the 1920s, as new techniques of physiological measurement were developed, researchers were able to measure objectively the bodily states James had been able to describe only subjectively. Their aim was to see how specific changes in blood pressure, pulse, and respiration correlated with the emotions the subjects said they experienced.
In the free-wheeling spirit of the time, some of the researchers imposed stresses on their subjects that would be considered outrageous today. A psychologist named Blatz, for instance, told his volunteers that the experiment they were taking part in was a study of heart-rate changes over a fifteen-minute period. Each volunteer was tied in a chair, blindfolded, wired to equipment that monitored pulse, breathing, and skin conductance, and left alone for a quarter of an hour. After three such sessions during which nothing happened—some subjects actually fell asleep—at some point in the fourth session Blatz threw a switch causing the chair, hinged in front and standing on a trap door, to drop backward. It was smoothly stopped by a door check after falling through a 60-degree arc. The volunteers exhibited a burst of rapid and irregular heartbeat, the abrupt cessation of breathing followed by gasping, and a surge of skin conductance. All reported feeling fear (and, later, either anger or amusement). Presumably, the fall was so sudden and unexpected that there was no anticipatory emotion; as in the James-Lange theory, the fear was the experience of the bodily changes produced by the fall.19
Carney Landis, a psychologist interested in the physiological sources of severe emotional upsets, must have been a remarkable salesman. In the early 1920s, he was able to persuade three volunteers to fast for forty-eight hours, go without sleep for the last thirty-six of them, be hooked up to blood-pressure and chest-expansion monitors, swallow a small balloon attached to a rubber tube to allow gastric contractions to be measured, have a similar device inserted into their rectums, and breathe into an apparatus that measured their carbon dioxide output as an index of metabolic rate—and at that point receive an electric shock as strong as they could bear without struggling until they signaled that they could stand it no longer.
The shock caused the blood pressure to shoot up, the pulse to race and become irregular, and the rectal contractions to cease. (The data on stomach contractions were not consistent.) But despite the volunteers’ commendable suffering for science, the results of the procedure were unclear. Although all three said they felt anger, they had little or no awareness of any specific physiological changes associated with and possibly causing the emotion. The only physical response Landis could find that regularly corresponded to a subjective state was that of surprise. An eye blink and a complex facial-bodily reaction immediately preceded awareness of the emotion and that, at least, was in accord with the James-Lange theory.20
But by 1927 other physiological experiments were yielding powerful evidence that contradicted the theory. They were the work of Walter Cannon (1871–1945), a distinguished investigator and theorist. Cannon was, like John B. Watson and James Gibson, one of those impecunious small-town youths who, though lacking important connections, was able in that era to scale the scientific heights through hard work and genius. He published research papers that attracted wide attention even before receiving his M.D. at Harvard, and, without any close links such as William James had had to the powers at that university, was appointed its George Higginson Professor of Physiology at the age of only thirty-five.
Although Cannon’s discipline was physiology, he had studied under James and was a friend of Robert Yerkes. It may have been these influences that led him, after years of exploring the control of digestion by the ANS, to turn to the physiology of the emotions. After much investigation, he came to regard the James-Lange theory as thoroughly wrong, and in 1927 he published a historic paper that seemingly demolished it.21 In the paper he offered five kinds of evidence based on his own and others’ research. Of the five, the following three were particularly convincing:
—Visceral changes usually occur one to two seconds after a stimulus, but emotional reactions generally take less time; they therefore precede the physical changes. (Although this was based on laboratory evidence, it is a common experience that immediately after a near-accident we feel fear—after which our heart pounds, we feel weak, we have a strange taste in our mouth, and more.)
—There are some differences among the visceral responses associated with various emotions, but they are not so differentiated or sensitive as to provide distinctive cues for the range of emotions that human beings experience.
—Cannon surgically severed the viscera of cats from the sympathetic nervous system, as C. S. Sherrington, a British physiologist, had previously done with dogs. In both cases all messages from the heart, lungs, stomach, bowels, and other viscera in which, according to James, emotions originate, were cut off from the brain. Nonetheless, wrote Cannon:
These extensively disturbing operations had little if any effect on the emotional responses of the animals. In one of Sherrington’s dogs having a “markedly emotional temperament,” the surgical reduction of the sensory field caused no obvious change in her emotional behavior; “her anger, her joy, her disgust, and when provocation arose, her fear, remained as evident as ever.” And in the sympathectomized cats all superficial signs of rage were manifested in the presence of a barking dog—hissing, growling, retraction of the ears, showing of the teeth, lifting of the paw to strike…22
Yet studies in succeeding decades, down to the present, continued to find evidence that in limited ways the James-Lange theory is correct. Three examples:
—A medical team at the Washington University School of Medicine found in 1969 that
injections of lactate (a byproduct of energy metabolism in the cells) produce the physiological symptoms associated with anxiety plus the subjective sensation of anxiety, the latter most strongly in those who are anxiety-prone.23
—In 1966 George Hohmann, a psychologist who was a paraplegic because of a spinal injury, interviewed twenty-five war veterans, all of whom had suffered severed spinal cords two years or more earlier. Hohmann asked them to describe episodes of fear, anger, sexual excitement, and grief experienced both before and since their injuries. They said that, except for grief, their emotions were different since the severing of the spine; there was a decline in quality, a muting or coldness to their feelings. Strikingly, the higher the lesion—and therefore the greater the number of body systems disconnected from the brain—the greater the change. As one man with a cervical (high) lesion said:
I sit around and build things up in my mind, and I worry a lot, but it’s not much but the power of thought. I was at home in bed one day and dropped a cigarette where I couldn’t reach it. I finally managed to scrounge around and put it out. I could have burned up right there, but the funny thing is, I didn’t get all shook up about it. I just didn’t feel afraid at all, like you would suppose.24
—Psychologists have long debated whether emotions are universal or relative; that is, whether people in different cultures feel the same feelings. For more than two decades, Paul Ekman of the University of California, San Francisco, Medical School, and his colleagues have studied the matter. They asked people in different cultures to express six basic emotions (anger, disgust, happiness, sadness, fear, and surprise), and found that their facial expressions were basically similar, though somewhat modified by cultural rules. Both Ekman and his colleagues, and Carroll Izard of the University of Delaware, have shown to people in a number of very different cultures photographs of actors expressing a number of emotions. Almost always, the viewers identified them correctly.