In the past few decades, parenting has become its own science. There are “parenting experts” who publish books on the proper way to raise a child. Countless sociological and psychological studies are being conducted about the proper way to breast feed, the proper way for children to sleep, the proper way to punish children, etc. Like most so-called experts, parenting experts are good at sounding sure of themselves, even if their information is questionable. And like all experts, parenting experts are adept at inspiring fear in their audiences of parents—the fear of raising bad children.
Parenting experts are good at presenting their opinions as objective truths; indeed, doing so is probably even more important to these experts’ success than the study of parenting itself. Experts wield a lot of power over laypeople, because the stakes of raising a child are so high—new parents will listen to a whole range of parenting experts because they want the best for their children.
One reason that parents are so easily convinced by parenting experts is that parents—and, in fact, all human beings—are bad at assessing risk. There are certain risks that scare people into changing their behavior—but these changes in behavior are often out of proportion with the risk itself. For example, one case of mad-cow disease in New Jersey prompted huge numbers of Americans to stop eating beef altogether. On average, people are far more frightened of planes than cars, even though cars are responsible for many more fatalities than planes. If one accounts for likelihood of death in a car versus likelihood of death in a plane, assuming equal time spent in both vehicles, then the overall likelihood of death is about the same.
Fear is an excellent example of how humans can be rational and irrational at the same. It’s probably rational to be afraid of mad-cow disease, since such a disease can be deadly. But it also seems fundamentally irrational to be more frightened of mad-cow disease than of heart disease, or more frightened of plane crashes than car crashes. Humans are good at recognizing danger, but they’re bad at assessing relative danger.
Why are people frightened? One persuasive theory about fear is that people tend to be frightened of things that pose an immediate threat, rather than a far-off danger. For example, Congress is more likely to pass a bill fighting terrorism than a bill fighting heart disease, even though heart disease kills far more people every year than terrorism. Heart disease is a far-off problem; terrorism, according to the authors, is “happening now.”
Humans tend to be more frightened of immediate threats than slow, gradual dangers (even though slow, gradual dangers are often the most lethal dangers of all). On paper, heart disease is far more dangerous than terrorism (and arguably easier to fight), but humans’ “immediacy bias” makes them more likely to fear and act against terrorism.
The authors return to the question of parenting. When parents try to make their children safer, it usually involves buying some new product—a product which won’t necessarily protect the child at all. For example, the car seat is often touted as a vital way to protect children in car crashes. In reality, though, the real benefit of putting a child in a car seat is that the child sits in the back seat of the car, rather than riding shotgun; the car seat itself doesn’t do much to save the child’s life.
The car seat example is a good illustration of how parents allow themselves to be manipulated by experts (and businesses trying to sell more merchandise). It’s also a good example of how the real benefits of a product or behavior can be different from the supposed benefits. In other words, it’s possible for parents to help their children without understanding exactly why.
Another important aspect of the parenting debate is the question, “how much do parents really matter?” On one hand, it seems clear that bad parenting can play a major role in determining a child’s future—this is why, as described previously, unwanted children born to parents who might otherwise have gotten an abortion are more likely to commit crimes as adults. But on the other hand, it’s not clear how much good parents can prepare their children for success in adulthood. Numerous studies of twins who were separated at birth suggest that genetics is responsible for about fifty percent of a child’s personality and abilities. Further studies suggest that parent nurturing accounts for a surprisingly small amount of a child’s development. For example, the Colorado Adoption Project, a study that followed the lives of 245 infants put up for adoption, found no correlation between the personality of the child and the personality of the child’s adopted parents. There’s still a lot of controversy about the role of parenting in a child’s development, with notable proponents on both sides of the debate.
This section introduces the classic dichotomy between nature and nurture. For the purposes of this chapter, “nature” and “genetics” are essentially synonymous. When the authors talk about nature in children, they’re essentially talking about the importance of children’s DNA. Numerous studies suggest that children grow up in the same way, regardless of their parents or their environments; such a conclusion would imply that genetics / nature plays the primary role in a child’s growth. But it also seems clear that nurture plays some role—surely parents have a lot of influence on their children’s behavior. This chapter will use economic methods to test the strength of parents’ influence on their children.
The authors ask us to consider two hypothetical children, one white, the other black. The white child is raised in Chicago by parents who spend a lot of time with him, reading with him and taking him to museums. When the white student proves himself to be good at math, his parents are proud. The black child is born in Florida, and his mother leaves him when he’s two years old. His father, who raises him, is an alcoholic, and sometimes beats him. The black child grows up selling drugs. It seems pretty clear that the white child is likely to have a successful life, while the black child is less likely. The question then becomes: to what extent can we attribute the two children’s situations to genetics, and to what extent can we attribute their situations to nurture?
The story of the two hypothetical children will show up throughout the second half of the book, including the Epilogue. On paper, the white child has tremendous advantages over the black child: he won’t be judged for the color of his skin, he has a good education, and his parents have the money to support him. The question that the authors propose is really twofold: first, to what extent do genetics and nurture influence these children’s performance in life, and second, to what extent are their performances unpredictable and not subject to either nature or nurture?
While this chapter will not attempt a comprehensive theory of child rearing, it will try to measure the role of parenting in a child’s success. A good place to start is academic performance, often taken as a benchmark of a child’s talent, intelligence, and hard work. In the Chicago Public School (CPS) system in the 1980s, it was mandated that any incoming high school freshman could apply to attend any high school in his or her district. This created a chaotic situation in which hundreds of thousands of teenagers were trying to get into the schools that were perceived as being the best in the district, submitting their test results, grades, etc. The only way to be fair was to use a lottery system for the students who applied to schools with more applicants than availabilities. As a result of the lottery system, there were thousands of students with identical test scores and grades sent to different schools. Thus, the CPS affair is a great opportunity to test the causational relationship between high school education and academic success.
The point of the CPS “study” is that children with identical academic abilities received different educations. In other words, children received different forms of “nurture”—some went to academically rigorous high schools, and others went to less successful high schools. This is seemingly an ideal opportunity to measure the influence of education on success—and therefore, the influence of nurture against nature. Right away, however, the study assumes that school tests are capable of measuring a student’s ability accurately, so that two students with the same test scores really do have the same ability. This is a somewhat questionable assumption (there are racial biases on many tests, and there are many smart students who don’t learn how to be good “test takers” until they’re in high school), but for the purposes of this case study we’ll assume that it’s true.
The CPS data leads to one conclusion: school choice barely matters at all in determining one’s academic success. When academically identical students (i.e., students who applied to attend an elite high school and had the same grades and test scores) were sent to different high schools, these students tended to have the same likelihood of graduating their high school and passing their federal-administered tests. Furthermore, students who claimed the right to attend another school in their school district weren’t any more likely to graduate or pass their federal tests than academically identical students who didn’t claim this right. In other words, a high school education seemed not to provide a measureable academic benefit for students.
The results of the CPS study suggest that a student’s education, at least at the high school level, has very little influence on the student’s academic success. In other words, a good student at a poor high school will get more or less the same test scores that he or she would have gotten at a good high school. This doesn’t necessarily mean that education has no influence on academic ability; as the authors admit, it’s possible that elementary and middle school play a major role in students’ academic abilities, so that students are unlikely to experience much change in their academic abilities by the time they’re teenagers.
However, there was one group of Chicago students who saw a dramatic change in their academic success as a result of the school choice laws: students of technical schools. Students who opted to transfer from traditional high schools to specialized trade schools tended to do better in their new academic environments. But apart from this small subgroup of students, the CPS school choice law seemed to have little to no success in improving students’ quality of education.
Like good economists, the authors treat their findings with nuance. It’s not all black or white: there were some students in Chicago who did benefit from changing schools. Trade students—i.e., students preparing for one specific job—would naturally benefit from attending a trade school instead of a typical high school.
For a long time, studies have shown an income gap between black and white adults. But when one takes into account the differences between the test scores that black and white students achieved when they were in the 8th grad, the income gap virtually disappears. In other words, it would seem, educators can reduce the adult income gap by making sure that black middle school students test at the same level as white middle school students.
The study of the income gap between black and white adults creates some major political problems. Studies would suggest that the best way to make sure that black and white adults are making the same amount of money is to ensure that black and white students get the same education. But as we’ve just seen, the CPS study seems to suggest that a “good education” doesn’t always improve academic performance.
Why is there a “testing gap” between white and black middle school students in the first place? There have been many theories: poverty, genetics, racial bias, etc. Some sociologists, such as the Harvard professor Roland Fryer, have argued that there is an unfortunately strong social incentive for black students to do poorly in school, since a black student who does well academically runs the risk of being mocked by his peers for “being too white” or “selling out.”
As we’ve already seen, social incentives exert a powerful influence on human behavior, and—according to Professor Fryer—in the case of many black students, the social incentive pushes them to reduce their own academic success. This behavior would otherwise seem irrational, except when social incentives are taken into consideration.
In the 1990s, the Department of Education (DoE) undertook a study of childhood development from kindergarten to the fifth grade; this study has proven to have important results for anyone seeking to understand the testing gap between white and black students. The study measured the students’ academic performance and compared this data with such other factors as race, family structure, socioeconomic status, etc. In order to understand this monumental study, sociologists and economists have used regression analysis. Regression analysis seeks to isolate the relationship between certain specific factors and other factors: for instance, the relationship between a child’s third-grade math scores and the child’s parents’ level of education. By itself, regression analysis cannot prove causation; it can only show correlation. Interpreting this correlative data, however, sociologists can attempt to prove causation.
The DoE study will take up the remainder of the chapter: it’s a monumental, comprehensive study of the different factors that might influence a child’s growth. In order to interpret this data, the authors will use mathematical methods. Regression analysis isn’t a perfect tool—it can never prove causation. This suggests that economics is both a “hard,” rigorous science and a “soft” discipline that requires a lot of interpretation. To understand the DoE data, the authors will have to use mathematics while also introducing their own subjective interpretations of the data.
The Department of Education’s study from the 1990s yields many important results. First, the black-white testing gap disappears when economists control for factors like income level, parents’ educational level, and mother’s age at the birth of her first child. (When the authors talk about “controlling” for certain factors, they mean that they eliminate the influence of these other factors. To control for the influence of parents’ education on white and black students, economists could focus their attention on students whose parents have identical levels of education.) These results are encouraging because they mathematically refute the racist notion that black students are inherently worse than their white counterparts: on the contrary, they show that black students underperform because of environmental factors—factors than can be improved.
In a sense, regression analysis is a way of performing a scientific “experiment” on data in hindsight. By isolating a few key variables, economists can measure how strongly one of the variables influences the others. The most encouraging conclusion from the DoE data is that the myth of white genetic superiority is just that—a myth. White students don’t outperform black students because they’re inherently smarter or more talented; they do so because, on average, they’re wealthier, healthier, and have stronger family support.
The Department of Education study suggests some ways for the federal government to reduce the black-white testing gap. However, it’s also a discouraging study, because it emphasizes the extent of the problem. There is an enormous disparity between the quality of different elementary schools in the U.S., and the quality of one’s elementary school education, in contrast to one’s high school education, would seem to have a dramatic influence on one’s academic success later on.
Comparing the DoE study with the CPS study yields some interesting results. While the quality of one’s high school education seems to play relatively little role in academic success, the quality of an elementary school education seems to matter greatly. This would suggest that elementary schools educate students during their most important “formative years.”
The Department of Education study isolated sixteen distinct factors that, one might think, play a major role in a child’s development. Eight of these sixteen factors have been shown to play a major role in the child’s development: 1) The child has highly educated parents; 2) The child’s parents have high socioeconomic status; 3) The child’s mother is thirty or older at the time of her first child’s birth; 4) The child had low birthweight; 5) The child’s parents speak English in the home; 6) The child is adopted; 7) The child’s parents are involved in the PTA (Parent Teacher Association); and 8) The child has many books in his house. The study also identified eight factors that are, somewhat surprisingly, not correlated with the child’s development: 1) The child’s family is intact; 2) The child’s parents recently moved into a better neighborhood; 3) The child’s mother didn't work between birth and kindergarten; 4) The child attended Head Start; 5) The child’s parents regularly take him to museums; 6) The child is regularly spanked; 7) The child frequently watches television; and 8) The child’s parents read to him nearly every day. The authors will now go through these sixteen factors, two at a time.
For the rest of the chapter, the authors will discuss the different variables that could influence a child’s future academic performance (and, by extension, a child’s overall quality of life). By discussing a wide range of hypotheses, Levitt and Dubner seek to eliminate their own biases and attempt an objective answer to the question of how a child should and shouldn’t be raised. For each hypothesis, the authors will do two things: first, they’ll note whether there’s a correlation or not; second, if there is a correlation, they’ll attempt to explain why. This combination of objective mathematical analysis and subjective interpretation is characteristic of economics.
It matters that the child has educated parents, because families with lots of schooling tend to value education. Also, education correlates with IQ, and IQ is strongly hereditary. However, it doesn’t seem to matter greatly if the child’s family is intact or not. We’ve already seen that family structure (number of siblings, whether or not both parents are alive, etc.) seems to have little impact on a child’s personality, so perhaps it makes sense that family structure has little impact on academic success, either.
It’s not surprising that children with educated parents tend to do well in school. But this isn’t necessarily because parents raise their children to be bright; perhaps they simply pass on their high IQs genetically. It’s also surprising that family structure doesn’t correlate with academic performance—but if the data doesn’t show a correlation, the authors will not attempt to argue for one.
It matters if a child’s parents have high socioeconomic status, because status correlates strongly with education and IQ, and intelligent parents tend to have intelligent children. However, moving to a better neighborhood doesn’t necessarily improve a child’s academic success. Nicer houses don’t “improve math or reading scores any more than nicer sneakers make you jump higher.”
As with IQ, it’s not immediately clear what the correlation between status and academic performance means—perhaps class tends to measure intelligence (the sociologist Charles Murray has argued this, somewhat controversially).
It matters if a child’s mother was thirty or older at the time of her first child’s birth, because women who are older when they have their children are likely to have had some advanced education or had significant career experience; therefore, she’ll want her children to have the same academic that she had. However, it doesn’t seem to matter if a mother stays home from work until her child is in kindergarten. The authors offer no explanation for this fact; it's just what the Department of Education data suggests.
Again, it would appear that a parent’s age correlates with the child’s academic success insofar as age correlates with advanced education. The DoE measures many different variables, but many of these variables seem to reflect the same fundamental metric: IQ (which has been found to be a very flawed measure of intelligence). Notice that the authors don’t try to explain the lack of correlation between staying at home and academic success: unlike many experts, the authors are realistic enough to admit that, at times, they don’t have the answers.
It matters if the child has a low birthweight, perhaps because being born prematurely foreshadows poor parenting (since often, babies are born prematurely because the mother drinks or smokes). However, there seems to be no correlation between academic success and attending Head Start, the federal preschool program. Many of the people who work for Head Start preschools don’t have college degrees of any kind, and the job pays poorly. Therefore, Head Start preschool programs are unlikely to attract talented teachers, or correlate with student success in the long run.
We’ve already seen that poor parenting can have a major influence on a child’s development; hence the high correlation of neglectful parents and a child’s criminal behavior. So it makes a certain amount of sense that low birthweight correlates with both poor parenting and poor academic performance (overall at least—certainly not in many individual cases).
It matters that the child’s parents speak English at home. This isn’t surprising, since language ability improves the more one uses the language. However, museum visits don’t correlate with academic success at all.
It would be surprising if English usage didn’t correlate with academic success in America, as a child needs to learn how to speak the language to succeed in an English-language school.
It matters if a child is adopted; indeed, there is a strong negative correlation between adoption and school test scores. In part, this might be because on average, mothers who offer up their children for adoption have lower IQs than mothers who keep their children. (The authors acknowledge that this might be a distasteful line of thinking.) However, there’s no correlation between spanking a child and its academic success.
Again the authors explain a correlation by tying the data back to IQ. Not for the first time, the authors suggest a hypothesis that might be offensive or disturbing (and certainly, there are intelligent women who have no financial option but to offer their children up for adoption).
It matters if a child’s parents are involved in the PTA (Parent Teacher Association). This is probably because the kinds of parents who attend PTA meetings tend to be educated and therefore motivated to help their children succeed. However, there is no proven correlation between TV watching and academic performance. There’s a strong bias against television when it comes to academic issues—and yet there are plenty of cases when watching TV can be educational.
PTA attendance would appear to correlate very strongly with education, social status, and perhaps IQ. One of the most surprising results of the DoE study is the lack of correlation between television watching and academic success. There’s nothing inherently wicked about watching TV—indeed, TV can even educate children (think of Sesame Street).
Finally, it matters that the child has many books in his or her home. However, there is no proven correlation between actually reading to a child every day and the child’s academic success. This seems exceptionally strange, since one would imagine that that reason why books correlate with academic success is, at least in part, because reading books makes you smarter. One possible explanation is that families with lots of books in the house tend to be well educated, hard working, and have higher IQs.
The authors save the most puzzling correlations for last. The fact that books correlate with academic performance would suggest that reading the books correlates, too. But surprisingly, the correlation between books and success seems to stem from the parents’ intelligence, wealth, and education, not their specific actions (i.e., reading to their children).
The authors return to the list of the sixteen factors that do and don’t correlate with academic performance. One important thing to note is that the eight factors that do correlate tend to describe things that parents are, (hard-working educated, career-oriented), while the eight factors that don’t correlate tend to describe things that parents do (read to children, go to museums, use corporal punishment).
The authors don’t just analyze correlations one-by-one; they perform a general analysis of the data, studying what the positively correlating variables have in common. The results of their “meta-study” emphasize the importance of essence (arguably, nature) and downplay the importance of action (arguably, nurture).
The authors now return to the nature-nurture debate. The Department of Education study could support the conclusion that parents’ genetic makeup makes a far bigger impact on a child’s development than any specific things that the parents do with their children. An overbearing parent who thinks that he can spank or teach his child into academic success is a little like a foolish politican who thinks he can use money to buy an election—as we already saw, money correlates with electoral success, but it can’t really change whether or not people like that politician.
The authors conclude by stressing the role of nature in parenting: a parent’s most important contribution to a child may well be the useful genetic traits the parent donates before the child is born. But although the authors question (and even mock) the idea that nurture can influence a child, it’s difficult to imagine how their descriptive conclusions would influence parents prescriptively. Regardless of the data, some parents will continue to read to their children, take them to museums, etc., and on an individual level this may have a direct effect.
The Department of Education’s study isn’t the only study of parental influence on child development. For example, one study analyzed adopted children in the U.S. and Britain. The study found that parents who adopt children tend to be smarter, better educated, and more highly paid than the child’s biological parents. While the foster parents’ education and money seemed to have little influence on the child’s early academic success, the study concluded that adoptees were more likely to attend college and get a well-paying job later in life. So adoptive parents, we might conclude, do play an important role in their adopted children’s long-term development.
The authors end the chapter with a major caveat. They’ve just concluded that, for the most part, it would seem that nature plays a larger role in a child’s early academic success than nurture does. But without a doubt, nurture influences other aspects of a child’s life, such as education, career, etc. Nurture may have little to do with a child’s IQ, but even so, it would be wrong to conclude that nurture exerts no influence on a child’s overall future. Good parenting is important because it prepares a child for success in many different ways.