Willpower

stereotypes of each other. The Indians regarded the Africans as lacking in future orientation and inclined to indulge rather than save, whereas the Africans regarded the Indians as joyless savers who lacked a zest for life. Mischel decided to test these stereotypes by asking children from each group to choose between two candy bars. One candy bar was bigger and cost ten times as much as the other, but a child who chose it would have to wait a week to get it. The smaller, cheaper one was available right away.
    Mischel found some support for the ethnic stereotypes, but in the process he stumbled on a much bigger and more meaningful effect. Children who had a father in the home were far more willing than others to choose the delayed reward. Most of the racial and ethnic variation could be explained by this difference, because the Indian children generally lived with both parents, whereas a fair number of the African children lived with a single mother. The value of fatherhood was also evident when Mischel analyzed just the African homes: About half of the children living with fathers chose the delayed reward, but none of the children in fatherless homes were willing to wait. Similarly, none of the Indian children living without a father were willing to wait.
    These findings, which were published in 1958, didn’t attract much attention at the time or in the ensuing decades, when it was dangerous to one’s career to suggest that there might be drawbacks to single-parent homes. (Daniel Patrick Moynihan was excoriated for making that suggestion.) Starting in the 1960s, changes in federal policies, social norms, and divorce rates led to a great expansion in the number of children raised by only one parent, usually the mother. No one wanted to sound critical of those mothers—and we certainly don’t want to denigrate their hard work and dedication. But eventually there were so many results like Mischel’s that the data could no longer be ignored. As a general rule—with lots and lots of exceptions, including Bill Clinton and Barack Obama—children raised by single parents tend not to do as well in life as children who grow up with two parents. Even after researchers control for socioeconomic factors and other variables, it turns out that children from two-parent homes get better grades in school. They’re healthier and better-adjusted emotionally. They have more satisfying social lives and engage in less antisocial behavior. They’re more likely to attend an elite university and less likely to go to prison.
    One possible explanation is that children in one-parent homes start off with a genetic disadvantage in self-control. After all, if the father (or mother, for that matter) has run off and abandoned the family, he may have genes favoring impulsive behavior and undermining self-control, and his children might have inherited those same genes. Some researchers have attempted to correct for this by looking at children who were raised by single parents because the father was absent for reasons other than having abandoned the family (like being stationed overseas for a long time, or dying at a young age). Predictably, the results were in between. These children showed some deficits, but their problems were not as large as those of the children whose fathers had voluntarily left the home. The evidence suggested that, as usual, children are shaped by a mixture of genetics and the environment.
    Whatever role is played by genes, there’s an obvious environmental factor affecting children in single-parent homes: They’re being watched by fewer eyes. Monitoring is a crucial aspect of self-control, and two parents can generally do a better job of monitoring. Single parents are so busy with essential tasks—putting food on the table, keeping the child healthy, paying bills—that they have to put a lower priority on making and enforcing rules. Two parents can divide the work, leaving them both with more time and energy to spend building the child’s character. More adult eyes make a difference—and quite a lasting difference, to judge from the results of a study that started more than six decades ago.
    In an attempt to prevent juvenile delinquency during the early 1940s, counselors visited more than 250 boys in their homes twice a month. They recorded observations about the family, the home, and the life of the boys. On average, the boys were about ten when the study began, and about sixteen when it ended. Decades later,