My editor at Die Welt Am Sonntag just gave me permission to share the original English version of my essay.  Enjoy.

The Science of Success: Why Parents Should Push Their Kids Less, and Enjoy Them More

Bryan Caplan

We worry about what a child will become tomorrow, yet we forget that he is someone today

Stacia Tauscher 

Modern parents see their children as their most important investments.  They want their children to succeed in the competitive world of the future – and know that success isn’t cheap.  Before your kids can succeed in the world of work, they must first succeed in the world of school.  Massive parental investment of time and money seems crucial.  Without it, won’t your children fail in both worlds?  Indeed, parenting seems so important that parents appear to face a tragic trade-off: To ensure your children’s academic and professional success, you often have to push them so hard that they end up resenting you.

But what makes us so certain that parents’ time and money are essential for kids’ success?  Most people point to the obvious fact that successful parents tend to have successful children.  Doesn’t this prove the power of upbringing?  No.  There are always two explanations for family resemblance.  One is upbringing.  The other is heredity.  Is it possible that success runs in families not because successful parents invest more in their kids, but because there are genes for success in school and work?

Unraveling the effects of upbringing and heredity is usually very difficult.  But over the last forty years, researchers have made astonishing progress by studying families that adopt, and families with twins.  If a child is adopted, then any family resemblance in success is almost surely due to upbringing.  Similarly, if identical twins (who shares all of their genes) are more similar than fraternal twins (who share only half of their genes), their extra resemblance is almost surely due to heredity.  Researchers have used these twin and adoption methods to figure out why diplomas and incomes run in families.  Their conclusions are shocking: Upbringing is much less crucial for success than most of us believe.

Let’s start with educational success.  In the 1950s, the Holt family set up a charity to help American families adopt disadvantaged Koreans.  The adopting families were unusually diverse: Applicants had to be married for at least three years, 25-45 years old, have no more than four children, and have earnings 25% or more above the poverty line.  Decades later, economist Bruce Sacerdote tracked down over 1600 of the Korean adoptees to see how much their adopting families influenced their success.  The effects were tiny.  If a mother had an extra year of education, her Korean adoptee finished five extra weeks of school; if a family had one extra child, its adoptee finished six fewer weeks of school.  Richer families and richer neighborhoods made no difference at all.  Another study of over two thousand Swedish adoptees found that moms mattered even less, and dads mattered a little more.

If parents matter so little for success in school, why does it run in families?  Heredity.  When twin researchers compare identical to fraternal twins, they find that identical twins are much more similar in their educational success. One major study looked at about two thousand pairs of American twins who served in World War II, and their children. Suppose you were separated from your identical twin at birth.  This veteran twin study implied that if you finished more schooling than four people out of five, the identical twin you never met would typically finish more schooling than three people out of four.  The effect of nurture, in contrast, was modest: If you were raised by an unskilled worker instead of a professional or manager, you typically finished one fewer year of school; if you had one extra sibling, you typically finished seven fewer weeks.  A big study of Australian twins’ education confirmed the power of nature and the limits of nurture.  Small, well-educated families boost their kids’ schooling by months, not years.

For many parents, admittedly, education is only a means to an end; they push academic success because they think it’s the path to financial success.  Counter-intuitively, though, the effect of parenting on income is even smaller than the effect of parenting on schooling.  In the Korean adoption study, adoptees raised by the richest families earned no more than adoptees raised by the poorest families.  Richer neighborhoods didn’t help either.  The only factor that made even a slight difference was family size: every sibling seemed to cut adult income by 4%.  The Swedish adoption study found a slightly larger effect, but still not much: If your dad made 10% more money, you make 1% more when you grow up.

Perhaps most impressively, though, a recent working paper by New York University’s David Cesarini uses the Swedish Twin Registry to track the lifetime earnings of over 5000 men born between 1926 and 1958.  Cesarini finds that parents have a modest effect on the earnings of men in their early twenties.  But after the age of 25, the effect of upbringing on earnings vanishes.  When children first become adults, their parents might help them find a good job – or support them so they don’t have to work.  Before long, however, young adults get on their own two feet – and stay there.

Parents clearly try mightily to help their kids succeed.  They buy educational toys, read bedtime stories, pay for expensive preschools, help them with their homework, reward them for good grades, and shame them for bad. They preach the value of hard work and persistence, praise high-earning occupations like doctor and engineer, pressure their kids not to major in poetry, and help them find their first jobs.  The surprising lesson of the science of success is that parents’ toil bears little fruit.  Your kids would have been about as successful in school and work if they’d been raised by a very different family.

This doesn’t mean that severe child neglect or abject poverty is harmless.  Twin and adoption studies focus on normal families that meet their children’s basic needs.  Researchers’ don’t ask, “Would this child have turned out differently if he were raised by wolves?”  They ask, “Would this child have turned our differently if he were raised by one of the other families we studied?”  When researchers report “no effect of family income on education,” this doesn’t mean that hungry kids learn as well as kids with full bellies.  It means that even the poorest families under observation were good enough to allow their children to reach their potential.

The right lesson to take away from twin and adoption research is that parents can relax without hurting their kids’ future.  Once you provide the basics, your children’s success is largely in their hands, not yours.  Of course, if you and your kids enjoy reading bedtime stories, working on school projects, and watching the financial news together, that’s wonderful.  But if you and your children aren’t having fun, the science of success shows that you can safely give yourselves a break.

Pushing kids less isn’t just easier for parents; it’s usually better for the whole family.  Riding your children “for their own good” has little effect on their future success.  But it damages one important outcome over which parents have much control: How your kids feel about and remember you.  In a word, their appreciation.

Twin and adoption researchers have studied appreciation for decades.  Genes play a role; identical twins paint somewhat similar pictures of their parents and home life even when raised apart.  But upbringing clearly affects appreciation, too.  One recent German twin study asked about 800 adults raised together to describe their families.  How accepting were their father and mother, and how well did family members get along? Siblings broadly agreed, but identical twins agreed only modestly more than fraternal twins.  Implication: Much of the resemblance stems from nurture, not nature.  Furthermore, an early study of 1400 middle-aged and elderly Swedish twins shows that the effect of upbringing on appreciation is very durable.  If you make a loving and harmonious family, your children won’t merely be grateful at the time.  The memories you create for them will likely last a lifetime.

People often fear that the science of success will be misused.  Twin and adoption research seem like handy excuses for lazy parents.  But scaling back misguided investments isn’t “lazy”; it’s common sense.  If your children’s future success is largely beyond your control, riding them “for their own good” is not just wasteful, but cruel.  The sentimental view that parents should simply cherish, encourage, and accept their children has science on its side.  Modern parents need to calm down and re-conceive family time as leisure, not work.  Having fun with your children may not prepare them for the future, but there are few more rewarding ways to spend your time.