by Morton Hunt
Extraordinary though it may seem today, the Terman and Miles test was used for many years before such assumptions were questioned. But as women’s social position changed in recent decades, so did many aspects of female personality; moreover, a mass of research findings by social-learning theorists and others challenged many of the traditional assumptions. A few examples of the hundreds in the research literature:
—Girls are indeed more fearful than boys of mice, snakes, and spiders—but largely because they learn early that it is more permissible for them than for boys to express fear.
—Girls spontaneously play with dolls more than boys do, a fact long taken as evidence that girls are innately more nurturing and helpful. But girls are more often given dolls to play with, a form of social training. Girls’ greater nurturance is at least partly learned.
—Elementary school girls appear to be more compassionate than boys, as judged by such criteria as their greater willingness to write letters to hospitalized children; boys, however, are very ready to be helpful when the activity called for is one they have been taught to think of as properly masculine. At the adult level, women seem readier to help people in distress than men, but chiefly in situations traditionally thought of as calling for female ministrations, such as tending a hurt child; males are readier to help in risky or strenuous situations. In sum, sex differences in helping behavior are partly or largely attributable to social learning.64
For a while, some feminists took the extreme position that virtually all personality and intellectual differences between the sexes are the result of social inequities, pressures, and conditioning. But as research evidence accumulated, it became clear that certain cognitive and personality differences are indeed influenced by biology. For instance:
—Women have become somewhat more aggressive in sports, business, and in experimental laboratory situations. But in social life most of them continue to be much less aggressive than men. The latter commit by far the larger share of family violence, rapes, homicides, and crime in general. The greater aggressiveness of males appears very early in life, well before most social influences come to bear; the findings strongly suggest that social learning, while it plays a large part, acts on and accentuates biologically built-in differences.
—Girls and women have the edge on boys and men in verbal ability, on the average, but are slightly inferior in spatial visualizing ability. The verbal difference appears early and the spatial difference before adolescence, when social influences become most influential; both, therefore, point to some degree of difference in the structure of the brain. A recent review of studies of the brain lists a number of minor differences between the female and the male brain—one such difference, a stronger linking between the two hemispheres in females, has been thought to account for females’ verbal edge over males—but the net conclusion is that “few data are available linking structural differences [in the brain] to functional sex differences.”
—Women are better than men at sensing the meaning of such non-verbal cues to emotion as posture, body movements, and facial expressions. In part this is probably an acquired skill, but some evidence, such as the appearance of these differences in early childhood, points to a biological predisposition produced by evolution. It may have been more important to the survival of the weaker sex to read body language.
—In a painstaking survey of recent data, Melissa Hines, a leading British neuroendocrinologist, reports that there are dramatic differences in “core gender identity” (the sense of oneself as male or female), but that other much-researched differences are quite small. She listed 3-D rotation ability (mental rotation of pictures of objects to see if they are the same as other objects), math ability, verbal fluency, spatial perception, and even rough-and-tumble play and physical aggressiveness. Some of these criteria favored males, some females, but in all cases the differences were small compared to the average sex difference in height. In any case, Hines concludes, “Variation within each sex is great, with both males and females near the top and the bottom of the distributions for every characteristic.65
The upshot is that while the radical feminist view is not justified by the findings, many traditional beliefs about innate differences in male and female personality have been disproved. Most male-female differences are now ascribed to social learning or to the interplay of social forces and biological factors, but some do appear to be innate. Kay Deaux, a psychologist at the City University of New York, concluded a review of research in the field with this comment:
What one may wish as a feminist is not necessarily what one sees as a scientist… Attempts to “disprove” the existence of sex differences have given way to arguments, both at the scientific and popular level, that differences do exist. Acknowledgment of the existence of differences should not, however, serve as a cap on efforts to understand the processes by which sex and gender have become influential in human behavior.66
But that temperate summary did nothing to quiet the long-running debate. Over the past two decades, many other studies of gender differences in personality have been published, some concluding that there are only trifling differences, others that there are significant differences, some holding that such differences as exist are culturally acquired, others that they are largely of genetic or biological origin. It would be tedious to exhibit examples of all this, but the distinguished researcher Stephen Kosslyn and co-author Robert Rosenberg recently summarized what has been learned:67
In general, personality differences between females and males are not very great, especially when compared with the large differences among people within each sex. For example, there are no notable sex differences in social anxiety, locus of control, impulsiveness, or reflectiveness.
Nonetheless, some consistent differences have been found. Women tend to score higher on traits reflecting social connectedness, which is a focus on the importance of relationships, men on traits reflecting individuality and autonomy. Women tend to be more empathic than men and report more nurturing tendencies [and] are better at spotting when their partners are deceiving them.
Males and females also differ in their degree of neuroticism, with men scoring lower. However, women generally score lower on anger and aggression.
The fact that a difference exists doesn’t tell us why it exists—what might be the role of biological or cultural factors. In spite of the evidence that culture and context shape gender differences, we must also note that there are biological explanations for these differences.
Which nicely illustrates a general truth about psychology that will become ever more apparent as our story proceeds: to some degree, opposed and seemingly incompatible theories about many a psychological phenomenon, pitted against each other for two and a half millennia, are both proving in the light of accumulating knowledge to be right.
Body, Genes, and Personality
The theory that male-female trait differences are biologically determined is part of the larger one that personality is innate. There are two related versions of this theory: one, the characteristics of an individual’s body influence personality; and two, personality is determined by specific genes or the interactions of certain genes.
The first version is nearly as old as psychology itself. Galen’s humoral theory of personality was one form it took in antiquity. Another was physiognomy, the view held from Greek times to today that the shape of the features and configuration of the body are accompanied by related personality traits. One example, of thousands: In The Canterbury Tales Chaucer pictures the sober, studious Clerk (scholar) as “not right fat” but “hollow,” the earthy, much-married Wife of Bath as “bold” of face, “red of hue,” and “gat-tothed” (gaps between the teeth, according to physiognomists, denote boldness and amorousness), and the vulgar Miller as stout, brawny, big-boned, and possessed of a gross nose with wide black nostrils.
In the early years of this century, body-personality theory took on the look of science when Ernst Kretschmer (1888–1964), a German
psychiatrist who worked in several mental hospitals in southern Germany, claimed he had found a relation between patients’ physiques and their personalities and mental states. Patients who were short-limbed, round of face, and thickset, he said, tended to have mood fluctuations and to be either very elated or very depressed; they were manic depressives. Those who were long-limbed, thin-faced, and slender tended to be introverted, shy, cold, and antisocial; they were schizophrenics. Those who had balanced physiques and muscle development were energetic, aggressive, and cheerful; they had other mental ailments.68
Kretschmer believed that both the body shapes and the personality types or mental states were produced by hormonal secretions. His theory, advanced in 1921 in Körperbau und Charakter (the English edition is called Physique and Character), attracted much favorable attention because it seemed to lend scientific support to ancient tradition. But other scientists poked holes in Kretschmer’s theory. Many people, they noted, do not fit neatly into any of the three categories—short, fat people often have personalities that should go with being tall and thin, and tall, thin people often behave like athletic types. Moreover, Kretschmer’s sample was skewed. Hospitalized schizophrenics are younger, on the average, than hospitalized manic depressives, and this alone might account for much of the difference he found in the distribution of body fat.69
But the body-type idea was appealing and soon had a new and more scientifically rigorous champion, William H. Sheldon (1899–1977), a physician and psychologist at Harvard. Shortly after Kretschmer’s book appeared in English, Sheldon began a study of “somatotypes” (body types) and over several decades collected data on the physical dimensions and personalities of normal people. (Late in life, he extended his studies to mental patients and delinquent boys.)
As a researcher, Sheldon spared himself no pains: he photographed no fewer than four thousand male college students in the nude and recorded their key physical measurements. From this mass of data he concluded that there are three basic body types much resembling Kretschmer’s: the endomorph, soft, rounded, and plump; the mesomorph, hard, square, big-boned, and muscular; and the ectomorph, tall, thin, and large of skull. These types, he believed, represent the special development of one or another of the three layers of cells that first differentiate in the embryo: the endoderm, from which arise the digestive tract and internal organs; the mesoderm, from which come bones and muscles; and the ectoderm, from which develops the nervous system.
To show the relation of personality traits to these somatotypes, Sheldon administered personality tests to two hundred of his subjects, and over the years gathered a wealth of other trait data from extensive interviews and his own observations of behavior. He found, as he had expected to, that a characteristic personality pattern was associated with each somatotype. The short, plump endomorph is usually social, relaxed, talkative, and sybaritic; the well-balanced mesomorph is energetic, assertive, courageous, optimistic, and sports-loving; and the tall, thin ectomorph is introverted, shy, intellectual, inhibited, and unsociable. Sheldon hypothesized that the genes determine which somatotype prevails as the fetus develops and thus which personality pattern the person manifests.70
His major publications, appearing in the 1940s, aroused much public and professional interest. But most psychologists found Sheldon’s typology simplistic and his research methods faulty: he paid little attention to the socio-economic background of his subjects, although a child of poverty is hardly likely to grow up a fat, jolly endomorph or a child of wealth and advantage a shy, cerebral ectomorph. Psychologists were particularly leery of the extremely high correlations—+.79 to +.83— Sheldon reported between the three somatotypes and their associated personality types. Correlations of that magnitude are so unusual in psychology, where most phenomena have multiple causes, as to suggest a fundamental flaw in research design. And indeed there was one. To quote one eminent authority, Gardner Lindzey:
There are a number of factors that would have to be considered in a full discussion of why so much co-variation is observed, but for most psychologists the explanation has seemed to lie in the fact that Sheldon himself executed both sets of ratings. Consequently, one may reason that implicitly Sheldon’s prior convictions or expectations in this area led him to rate both physique and temperament in a consistent manner, whatever may have existed in reality.71
Supporters of Sheldon’s views sought to repair this shortcoming in later studies; they had the somatotype ratings made from photographs by raters who never met the individuals, and the personality evaluations made by other raters from questionnaire data rather than interviews. These studies confirmed Sheldon’s connections between body type and personality, but with considerably smaller correlations.72 Even these data, however, might not prove a direct link between somatotypes and personality; the link could be indirect and social. Because people expect strong muscular mesomorphs to be leaders, weak skinny ectomorphs to avoid physical competition and rely on their minds, children, sensing what people expect of them, may come to behave accordingly.73
Although the somatotype theory attracted attention and sparked much research during the 1950s, the trenchant criticisms of it, and the fact that the theory was hereditarian and thus out of tune with the prevailing liberalism of the time, caused it to fade in influence. By the 1960s, according to the distinguished historian of American psychology Ernest Hilgard, it had almost vanished from the scene. But stronger evidence of the innateness of personality, or of at least a predisposition toward one pattern or another, has continued to crop up.
In the 1940s, Alexander Thomas and Stella Chess, psychiatrists at the New York University Medical Center, began studying individual temperamental differences in infants and young children. (“Temperament,” a part of personality, is the individual’s characteristic way of reacting emotionally to stimuli and situations.) Thomas and Chess collected data on babies’ behavior starting at birth, partly by personal observation and partly by asking parents specific questions, such as how the infant reacted to the first bath or the first mouthful of cereal. They found good evidence of what every mother of more than one child knows, namely, that infants are temperamentally different from one another from their first hours on.
After years of study, Thomas and Chess specified nine differences that are manifest from the beginning of life. Some babies are more active than others; some have regular rhythms of eating, sleeping, and defecating while others are irregular and unpredictable; some like everything new (they gobble up the first spoonful of new food) while others do not (they spit it out); some adapt quickly to change, while others are distressed by any alteration of their schedules; some react to stimuli strongly, either laughing or howling, while others only smile or whimper; some are happy most of the time, others unhappy; some seem aware of every sight, sound, and touch, while others respond only to some stimuli and ignore others; some can be easily distracted if they are uncomfortable, but others are more single-minded; and some have a good attention span and will play with one toy for a long time, while others shift quickly from one activity to the next.
Summing up, Thomas and Chess found that about two thirds of all babies show a characteristic temperament early in infancy. Four out of ten are “easy” (placid and adaptable), one out of ten is “difficult” (irritable and hard to pacify), and one out of six is “slow to warm up” (moderately fussy or apprehensive but able to get used to things and people).74
As Thomas and Chess watched some of the children develop to near adulthood, they were initially impressed by how often the temperament of a baby remained substantially unchanged in childhood and adolescence. Later, their more detailed findings led them to a more qualified conclusion. Frequently, some or many aspects of the basic temperament were modified by such major events as a serious accident or illness, or such changes in the environment as the death of a parent or a dramatic alteration in the family’s economic status. But when there were no such events or changes in the environment, the temperamental style of the first day
s of life was likely to be the temperamental style of the grown person.75
Even more impressive evidence that personality is partly innate has come from research in behavior genetics. This specialty, formerly somewhat outside mainstream psychology but now becoming more central to it, deals with genetic influences on psychological characteristics. Its major method of inquiry, originated by Galton, is to see to what extent people related to each other in differing degrees have similar mental abilities, personality, and achievements. First cousins have an eighth of their 25,000 to 30,000 genes in common, siblings a half, and identical twins all. If genes exert an influence on psychological development, the closer the genetic relationship between two people, the more psychologically alike they should be.
A vast amount of research conducted over the past half century has shown this to be the case. Some studies have shown that the closer the genetic relationship, the more alike the people are in mental health or illness.76 Others have found the same to be true of general intelligence and of specific mental abilities.77 And in the past three decades a number of geneticists and psychologists have found that the closer the genetic relationship, the more alike the personalities of the individuals.
Some of the personality research is based on analyses of the correlations in the traits of fraternal twins and of identical twins; consistently, the identicals are much more alike than the fraternals. Still, if they have been reared together in the same home, the evidence is less than perfect; they have had the same or very similar environmental influences all along (and identical twins, in particular, are even treated alike by their parents). For that reason, the best data—but the hardest to gather because instances are so rare—come from studies of identical twins separated at or soon after birth and raised in different homes and areas, where the environments are at least somewhat dissimilar.
