The Nurture Assumption: Why Children Turn Out the Way They Do

“The goal of the later generations of researchers was not to find out whether parents influence their children’s development but to discover how they influence it. The procedure became standardized: you look at how the parent rears the child, you look at how the child is turning out, you do that for a fair number of parents and children, and then, by putting together all the data and looking for overall trends, you try to show that some aspect of the parent’s child-rearing method had an effect on some characteristic of the child.”

Harris frames psychology’s Freudian roots, furthered by Behaviorists John B. Watson and B. F. Skinner, as grounded in a false assumption. To her, many studies are inherently flawed because they assume parenting is the most important influence in child development. This quote challenges the reader to consider how bias may inform how psychologists design and report studies.

“In both kinds of studies, the researchers collect data on the goodness of the style (life or childrearing) and the goodness of the presumed outcome (health or child). In both kinds of studies, the goal is to show that if you do the right thing you will obtain the desired result. In both kinds of studies, the results come in the form of correlations, and correlations are intrinsically ambiguous.”

Harris compares correlational studies from epidemiology and psychology. This quote casts doubts on the legitimacy of correlation reporting, since some researchers draw conclusions from correlations which are impossible to prove. This reporting assumes parenting decisions produce certain traits in children.

“Given how similar the reared-apart twins are, you probably think that the reared-together ones must be as alike as two copies of your annual Christmas letter. In fact, they are no more alike than identical twins separated in infancy and reared in different homes.”

Harris refers to twin studies to demonstrate parenting and home do not make siblings’ personalities more alike than if they were raised apart. This quote frames similarities between biological siblings as likely genetic, rather than the product of shared parenting.

“It is true: what you learn in one context will not necessarily work in another. A child who cries at home gets—if he’s lucky—attention and sympathy. In nursery school, a child who cries too much is avoided by his peers; in grade school he is jeered at. A child who acts cute and babyish for her daddy evokes a different reaction from her classmates. Children who get laughs for their clever remarks at home wind up in the principal’s office if they don’t learn to hold their tongue in school. At home the squeaky wheel gets the grease; outside, the nail that sticks up gets hammered down.”

Harris argues everyone develops different personalities in different social contexts. This quote’s examples reinforce the theme of Children’s Agency and Individuality, as children do not develop one static personality in response to how they are parented at home.

“It is common for immigrant children to use their first language at home and their second language outside the home. Give them a year in the new country and they are switching back and forth between their two languages as easily as I switch back and forth between programs on my computer. Step out of the house—click on English. Go back in the house—click on Polish. Psycholinguists call it codeswitching.”

Language is a powerful example of how social contexts inform human behavior. Harris’s explanation of codeswitching suggests that if parents were truly a primary influence in child development, children likely would not learn a new language as easily as they do.

“Much of the evidence used by socialization researchers to support their belief in the nurture assumption consists of observations of the child’s behavior in the presence of the parents, or questionnaires about the child’s behavior filled out by the mother. Researchers want to demonstrate effects of the home environment—for example, after a divorce—so they observe the children in the home, a home where a lot of unpleasant things have happened recently. Worse yet, they ask the parents—not exactly what you’d call neutral observers, especially after the turmoil of a divorce—to fill out a questionnaire about the child’s behavior.”

Harris casts doubt on the veracity of socialization research by explaining it comes from children’s parents. This quote supports her argument that parents only see one of their children’s personalities, their “home” self, and are ignorant to how they may act at school or in other contexts.

“To people reared in traditional cultures, the way North Americans rear their children is ‘unnatural.’ We justify our methods by saying we want our children to be independent, and indeed our children do appear to be pretty independent. But there is no proof that putting them to bed by themselves is what makes them independent. They are put to bed by themselves because we believe children should be independent. Child-rearing practices are the product of a culture, not necessarily the baton with which the culture is passed from one generation to the next.”

In this quote, Harris uses a relatable example—the practice of children sleeping in separate rooms from their parents—to question how researchers interpret correlations between parenting and children’s traits. It reinforces her argument that parenting practices are rooted in culture-specific beliefs about childhood, and as such, are subjective.

“But childrearing is not physics. The research that gets done and the interpretations that get put on it are without a doubt the product of our culturally conditioned views of childhood and parenting—views that change, sometimes dramatically, sometimes in less than a generation. Because childhood and parenting are intrinsically emotional topics, it may be impossible to test theories about them with the same dispassion used to test theories about neutrinos and quarks.”

Harris acknowledges the difficulty in designing objective studies on children and parents, arguing this type of research is more prone to bias. Thus, this quote encourages the reader to consider how different studies may have been affected by “culturally conditioned views of childhood and parenting.”

“The nurture assumption implies that children are born with empty brains which their parents are responsible for filling up. Obviously, children do learn things from their parents. But they do not learn only from their parents. Although much of what human children need to know is learned after they are born, there are good evolutionary reasons why it wouldn’t make sense to allow parents to monopolize that learning.”

In this quote, Harris uses evolutionary logic to dismantle the nurture assumption and support her group socialization theory. She encourages the reader to see children not only as members of nuclear families, but multifaceted communities. Historically, humans lived communally and depended on connections outside of their families—these experiences continuing to inform instincts in the present.

“The problem is that you can’t just look to see whether a child is or is not attached to his mother, because all normal children are attached to their mothers (assuming they have a mother to be attached to). Even children whose mothers have neglected or abused them are attached to their mothers.”

Harris questions simplistic notions of attachment, as seen in developmentalist Mary Ainsworth’s study—which equated one affectionate interaction with a secure attachment. This quote bolsters her claim that some researchers continue to build on assumptions about attachment and relationships.

“Monkeys reared with mothers but without peers are happy enough in infancy but have serious problems later on, when they are caged with other monkeys. The peerless ones […] show ‘no disposition to play together’ and are abnormal in their social behavior—in fact, only the monkeys raised in total isolation are more abnormal.”

Harris cites research on monkeys to demonstrate The Importance of Peer Groups in primates. While scientists cannot perform such research on humans for ethical reasons, these findings still provide some insight into socialization and reinforce Harris’s evolutionary argument for her group socialization theory.

“Polynesian children are expected to behave in a restrained and self-effacing manner with adults: the adult is supposed to initiate and control all interactions, the child is supposed to be compliant and undemanding. With their peers they are allowed to behave in a more assertive fashion.”

Harris uses Polynesian culture to debunk the idea that children imitate adults and aspire to act like them. In other words, she dismantles a foundational idea in the nurture assumption—that children look to their parents as their primary influence.

“The only way we can tell which environmental factors are having an effect is to look at cases in which they do not work together, and that is why I keep coming back to the immigrant family. When the parents belong to one culture and the rest of the community belongs to a different culture, we can at least distinguish the effects of the parents from the effects of outside-the-family influences.”

Harris considers immigrant families a more reliable subject for socialization studies due to the clearer distinction between their parental influence and other environmental factors. This quote reminds the reader that many studies on child development do not adequately separate parental influence from that of peers and teachers.

“But the two cultures of a code-switcher, though separate, are not equal. The children of immigrants bring the culture of their peers home to their parents; they do not, as a rule, bring the culture of their parents to their peers. […] When the culture outside the home differs from the culture inside it, the outside culture wins.”

Harris analyzes how people of different languages “code-switch,” or change languages (or dialects) depending on social context. She argues that since children are more readily influenced by their peers’ language than that of their parents, they must also be more influenced by peers’ behavior and expectations.

“Children are not incompetent members of the adults’ society: they are competent members of their own society, which has its own standards and its own culture. Like the prisoners’ culture and the Deaf culture, a children’s culture is loosely based on the majority adult culture within which it exists. But it adapts the majority adult culture to its own purposes and it includes elements that are lacking in the adult culture. And—like all cultures—it is a joint production, the creation of a committee. Children cannot develop their own cultures, any more than they can develop their own languages, except in the company of other children.”

Harris rebukes traditional models of child development which regard children as incompetent or incomplete adults. By framing children as capable co-creators of their own subcultures, she emphasizes that they do not passively receive influence from others, but impact parents and peers in turn. This quote supports the themes of Children’s Agency and Individuality and The Importance of Peer Groups.

“The most important years for group socialization are the years of middle childhood, from six to twelve. During all that time, children in our society—a society that provides them with a plethora of potential companions—spend much of their free time with peers of their own sex. They are socialized—that is, they socialize each other, they socialize themselves—not just as children but as girls or as boys. This gendered socialization is not simply a consequence of spending time with other members of one’s sex or even of liking the members of one’s sex better: it is a consequence of self-categorization.”

A key feature of Harris’s group socialization theory is children’s instinct to socialize through play and other activities. To her, children instinctively differentiate themselves based on assigned sex, a key aspect of their social lives as they spend more time with fellow boys or girls.

“According to an article in the journal ‘Science,’ children do better in school if they come from homes that have a dictionary and a computer. The writer evidently thinks that it’s the home that makes the difference. I think it’s the culture, not the home. Homes that contain a dictionary and a computer are likely to be found in middle-class neighborhoods populated by college-educated parents. Such neighborhoods foster a pro-reading, pro-education culture. The children bring this culture with them to the peer group and the peer group retains it because it is something they have in common.”

Harris questions another writer’s interpretation of causality in child development. This quote again demonstrates how correlations can be interpreted in different ways, making them unreliable indicators of children’s behavior.

“Leaders can bring people together or divide them up. Some of the things that teachers do nowadays, with the best of intentions, have the unintended result of making children more aware of the ways they can be sorted into social categories. I believe that a teacher’s job is not to emphasize the cultural differences among the students (that can be done at home by the parents) but to downplay them. A teacher’s job is to unite students by giving them a common goal.”

Harris considers how teachers can help children relate to peers harmoniously. This quote builds on her theory by offering advice on how to ensure children have the connections they need to learn from peers.

“Is she saying that teenagers commit illegal acts because they want to be like adults? That can’t be right! If teenagers wanted to be like adults they wouldn’t be shoplifting nail polish from drugstores or hanging off overpasses to spray i love you lisa on the arch. If they really aspired to “mature status” they would be doing boring adult things like sorting the laundry and figuring out their income taxes. Teenagers aren’t trying to be like adults: they are trying to distinguish themselves from adults!”

Harris refutes the notion that teenagers are eager to emulate adults, and points to stereotypical behavior to prove it. This quote emphasizes that teens, like younger children, develop their own subcultures which are important to their identities. In doing so, they prove they are more influenced by each other than they are by their parents or other adults.

“Now you can see why teenagers are so annoyed when adults take over their styles of dress or speech—why they are forced to invent new ones. They have attained an adult size and shape, more or less, but they don’t want to be mistaken for grownups. They need ways of signaling their group identity and loyalty to the other members of their group. The big question of adolescent life—the unspoken question that teenagers are constantly asking each other and constantly answering—is: Are you one of us or one of them? If you’re one of us, prove it.”

This quote frames teens as their own peer group, unlike cultures in which one is considered either a child or an adult. Harris argues teens develop their own customs to signal belonging, and that these customs are intentionally different from adult norms.

“It is true that if you ask children who influences them more—what they’d do if their parents and their friends gave conflicting advice—younger children are more likely to say they’d listen to their parents. But they are asked this question out of context and the one who’s asking is a grownup. They may interpret the question as meaning ‘Whom do you love more?’ and of course they love their parents more than they love their friends. The question has been answered by the relationship department of their mind but it is the group department that will, in the long run, determine how they will behave when they’re not at home.”

Harris claims surveys of children are unreliable, as children cannot objectively report their influences and are susceptible to changes in personality depending on age or social context. She claims children are biased towards considering their parents their primary influence, since they often love them more than their friends.

“I ask you to promise not to go around telling people that I said it doesn’t matter how you treat your children. I do not say that; nor do I imply it; nor do I believe it. It is not all right to be cruel or neglectful to your children. It is not all right for a variety of reasons, but most of all because children are thinking, feeling, sensitive human beings who are completely dependent on the older people in their lives. We may not hold their tomorrows in our hands but we surely hold their todays, and we have the power to make their todays very miserable.”

Harris clarifies the importance of parenting, refuting critics who claim her theory excuses parental neglect or abuse. This quote encourages the reader to not only view childhood as a step to adulthood, but a meaningful experience in itself.

“But by far the most important thing that money can do for children is to determine the neighborhood they grow up in and the school they attend. […] The medium through which the cultures are passed down cannot be the family, because if you pluck the family out of the neighborhood and plunk it down somewhere else, the children’s behavior will change to conform with that of their peers in their new neighborhood. It’s the neighborhood, not the family.”

Harris uses changes in home and peer groups to convince the reader that children’s surroundings are a powerful influence. Children tend to assimilate to the rules and values of their peers as a key part of their socialization (and survival) instinct—especially in a new place.