The Course of Human Development
A serious limitation of attachment theory is its failure to recognize the profound influences of social class, gender, ethnicity, and culture on personality development. These factors, independent of a mother's sensitivity, can be as significant as the quality of the early attachment. By the age of 4 or 5, every child perceives that he or she shares more features with some adults, especially those in the family, than with most others, based on hair style, facial attributes, skin color, and other characteristics. This perception of observable facts is accompanied by the irrational inference that perhaps the child also shares features that he or she doesn't see. For example, a 6-year-old girl with an attractive, competent, well-liked mother is tempted to conclude that she, too, possesses these traits. If the child feels moments of pride because of this inference, we say that she's identified with her mother. However, if the mother is plain, overweight, illiterate, and drinks too much, her daughter will mistakenly assume that perhaps these less desirable traits comprise parts of her personality, and she'll feel ashamed or anxious.
Consider an example of the power of identification. I recall talking with a 35-year-old Polish journalist in 2002 who grew up in anti-Semitic Poland believing that both of her parents were Roman Catholic. But when this young woman turned 20, her mother told her that she (the mother) had been Jewish, and had converted after marrying. In response, the young woman fell into a deep depression, which lasted several years. Her ethnic and religious identifications had been transformed from favored categories to those that were despised in her society. In an instant, she'd become The Hated Other. This change in belief about the self, based on discovering previously unknown information about one's family, can alter the sense of personal identity and precipitate a depression—even in an adult who's been a securely attached infant.
Research has demonstrated that social and economic factors have a powerful influence on development. The strongest predictor of adult depression or anxiety in many cultures is growing up in a disadvantaged social class. For example, Mississippi has a larger proportion of minority residents living in poverty than North Dakota, and the incidence of depression in Mississippi is three times that of North Dakota, according to the Centers for Disease Control. In fact, if two groups of psychologists were asked to predict the personality traits and incidence of pathology in 5,000 randomly selected 30-year-olds, and the first group knew only the social class in which the child had been reared, while the other group knew only the mother's sensitivity and the nature of the child's attachment during the first two years of life, the first group would make far more accurate predictions about personality and mood disorders.
Why does a disadvantaged social class position predict mood disorders, criminal careers, or addictions? One reason is that children identify with their class, which in the United States and Europe is defined by type of work, education, and income. Children belonging to less-advantaged class categories feel less potent, less virtuous, and possess a weaker sense of agency because of their identification. These traits are reflected during childhood—long before a depression or anxiety disorder develops—in lower school motivation, poorer grades, hostility to more advantaged peers, and less willingness to persist with difficult challenges.
Some influences on development that are important are less obvious, especially the person's historical era and culture. Children born in colonial America in the early 18th century were subject to harsh discipline during their socialization. But because most children experienced this form of discipline, they didn't grow up believing that their parents hated or rejected them, but became well-adjusted adults in their particular cultural setting. Shy, timid children are at risk for social anxiety in contemporary America because our culture values the outgoing, popular child who's exuberant. But this risk is far lower for children growing up in China and South Korea, where shyness and reticence are regarded as acceptable, adaptive, even praiseworthy traits.