In brain terms, we can speculate, the limbic circuitry would send alarm signals in response to cues of a feared event, but the prefrontal cortex and related zones would have learned a new, more healthy response. In short, emotional lessons—even the most deeply implanted habits of the heart learned in childhood—can be reshaped. Emotional learning is lifelong.
14
Temperament Is Not Destiny
So much for altering emotional patterns that have been learned. But what about those responses that are givens of our genetic endowment—what of changing the habitual reactions of people who by nature are, say, highly volatile, or painfully shy? This range of the emotional compass falls under the sweep of temperament, the background murmur of feelings that mark our basic disposition. Temperament can be defined in terms of the moods that typify our emotional life. To some degree we each have such a favored emotional range; temperament is a given at birth, part of the genetic lottery that has compelling force in the unfolding of life. Every parent has seen this: from birth a child will be calm and placid or testy and difficult. The question is whether such a biologically determined emotional set can be changed by experience. Does our biology fix our emotional destiny, or can even an innately shy child grow into a more confident adult?
The clearest answer to this question comes from the work of Jerome Kagan, the eminent developmental psychologist at Harvard University.1 Kagan posits that there are at least four temperamental types—timid, bold, upbeat, and melancholy—and that each is due to a different pattern of brain activity. There are likely innumerable differences in temperamental endowment, each based in innate differences in emotional circuitry; for any given emotion people can differ in how easily it triggers, how long it lasts, how intense it becomes. Kagan's work concentrates on one of these patterns: the dimension of temperament that runs from boldness to timidity.
For decades mothers have been bringing their infants and toddlers to Kagan's Laboratory for Child Development on the fourteenth floor of Harvard's William James Hall to take part in his studies of child development. It was there that Kagan and his coresearchers noticed early signs of shyness in a group of twenty-one-month-old toddlers brought for experimental observations. In free play with other toddlers, some were bubbly and spontaneous, playing with other babies without the least hesitation. Others, though, were uncertain and hesitant, hanging back, clinging to their mothers, quietly watching the others at play. Almost four years later, when these same children were in kindergarten, Kagan's group observed them again. Over the intervening years none of the outgoing children had become timid, while two thirds of the timid ones were still reticent.
Kagan finds that children who are overly sensitive and fearful grow into shy and timorous adults; from birth about 15 to 20 percent of children are "behaviorally inhibited," as he calls them. As infants, these children are timid about anything unfamiliar. This makes them finicky about eating new foods, reluctant to approach new animals or places, and shy around strangers. It also renders them sensitive in other ways—for example, prone to guilt and self-reproach. These are the children who become paralyzingly anxious in social situations: in class and on the playground, when meeting new people, whenever the social spotlight shines on them. As adults, they are prone to be wallflowers, and morbidly afraid of having to give a speech or perform in public.
Tom, one of the boys in Kagan's study, is typical of the shy type. At every measurement through childhood—two, five, and seven years of age—Tom was among the most timid children. When interviewed at thirteen, Tom was tense and stiff, biting his lip and wringing his hands, his face impassive, breaking into a tight smile only when talking about his girlfriend; his answers were short, his manner subdued.2 Throughout the middle years of childhood, until about age eleven, Tom remembers being painfully shy, breaking into a sweat whenever he had to approach playmates. He was also troubled by intense fears: of his house burning down, of diving into a swimming pool, of being alone in the dark. In frequent nightmares, he was attacked by monsters. Though he has felt less shy in the last two years or so, he still feels some anxiety around other children, and his worries now center on doing well at school, even though he is in the top 5 percent of his class. The son of a scientist, Tom finds a career in that field appealing, since its relative solitude fits his introverted inclinations.
By contrast, Ralph was one of the boldest and most outgoing children at every age. Always relaxed and talkative, at thirteen he sat back at ease in his chair, had no nervous mannerisms, and spoke in a confident, friendly tone, as though the interviewer were a peer—though the difference in their ages was twenty-five years. During childhood he had only two short-lived fears—one of dogs, after a big dog jumped on him at age three, and another of flying, when he heard about plane crashes at age seven. Sociable and popular, Ralph has never thought of himself as shy.
The timid children seem to come into life with a neural circuitry that makes them more reactive to even mild stress—from birth, their hearts beat faster than other infants' in response to strange or novel situations. At twenty-one months, when the reticent toddlers were holding back from playing, heart rate monitors showed that their hearts were racing with anxiety. That easily aroused anxiety seems to underlie their lifelong timidity: they treat any new person or situation as though it were a potential threat. Perhaps as a result, middle-aged women who remember having been especially shy in childhood, when compared with their more outgoing peers, tend to go through life with more fears, worries, and guilt, and to suffer more from stress-related problems such as migraine headaches, irritable bowel, and other stomach problems.3
THE NEUROCHEMISTRY OF TIMIDITY
The difference between cautious Tom and bold Ralph, Kagan believes, lies in the excitability of a neural circuit centered on the amygdala. Kagan proposes that people like Tom, who are prone to fearfulness, are born with a neurochemistry that makes this circuit easily aroused, and so they avoid the unfamiliar, shy away from uncertainty, and suffer anxiety. Those who, like Ralph, have a nervous system calibrated with a much higher threshold for amygdala arousal, are less easily frightened, more naturally outgoing, and eager to explore new places and meet new people.
An early clue to which pattern a child has inherited is how difficult and irritable she is as an infant, and how distressed she becomes when confronted with something or someone unfamiliar. While about one in five infants falls into the timid category, about two in five have the bold temperament—at least at birth.
Part of Kagan's evidence comes from observations of cats that are unusually timid. About one in seven housecats has a pattern of fearfulness akin to the timid children's: they draw away from novelty (instead of exhibiting a cat's legendary curiosity), they are reluctant to explore new territory, and they attack only the smallest rodents, being too timid to take on larger ones that their more courageous feline peers would pursue with gusto. Direct brain probes have found that portions of the amygdala are unusually excitable in these timid cats, especially when, for instance, they hear a threatening howl from another cat.