example (performance on the 1970 California Achievement Test), kids in the program scored far better than the controls: a whopping 49 percent vs. 15 percent. Among girls, though not boys, more graduated from high school (84 percent vs. 32 percent).
As adults, those who had been in the program were less likely to commit crimes and more likely to hold steady jobs. They made more money, more often had a savings account, and were more likely to own a home. Economists calculated that the return on society’s investment in such a program was 7 to 10 percent, higher than what you’d historically get in the stock market. If each tax dollar was invested from age 4 through 65, it would return “in present-value terms $7 to $12 back to society,” one analysis said.
Seed and soil
The HighScope study is a prime example of the importance of environment in raising children. But nature plays just as large a role. Often, they are tough to separate, as in this old joke: A third-grade boy comes home and hands his father his report card. His father looks at it and says, “How do you explain these D’s and F’s?” The boy looks up at him and says, “You tell me: Is it nature or nurture?”
I was once at a lively, noisy science fair with my own third-grade son, and we were touring some of his classmates’ efforts. Several experiments involved seeds, soil, and growth curves. One memorable little girl took great pains to explain to us that her seeds had started with identical DNA. She had planted one in a nutrient-rich soil and watered it carefully. She had planted the other in a nutrient-poor soil and watered it carefully, too. Time passed. The seed nurtured with terrific soil made a terrific plant, which she proudly let me hold in my hands. The seed nurtured in poor soil made a pitiful, withered plant. She let me hold that, too. Her point was that the seed material provided identical growth opportunities for both plants, but that an equal start was not enough. “You need both seed and soil,” she explained to me—nature and nurture—to get the desired results.
She’s right, of course, and it’s a metaphor I use in this book to organize the research on raising smart and happy kids. There are some factors parents can’t control and some they can. There’s seed, and there’s soil. All of the nurture in the world won’t change the fact that 50 percent of your child’s potential is genetic. Good news: As a parent, you can only do your best. That said, even as a professional geneticist, I am convinced we can exert far more influence over our kids’ behavior than is popularly imagined. It’s a very, very big job that takes a lot of work. The reason has deep evolutionary roots.
Why do we need parenting, anyway?
It’s a question that bothers many evolutionary scientists: How come it takes so long to raise a human child? Aside from perhaps a whale or two, we have the longest childhood on the planet. Where did this decades-long sojourn come from, and why don’t other animals have to go through what we do? Just a couple of delightful things we human parents endure:
I feel so drained. JJ pooped in his diaper right after I got him off the potty, he threw up on the carpet, tipped his potty over and got pee on the carpet again, then he peed on the carpet AGAIN at bath time. I’ve come so far and feel like I can’t do this mommy thing, then I realize—I’m doing it …
Both my husband and I have rather colorful vocabularies. We never swear at our dear daughter, and try to watch our language around her, but we’re obviously failing miserably—my mom asked her what her baby’s name is, and she responded, “Asshole.” Oops.
Yes, you have to teach children everything—even how to regulate their body fluids. And they are built to learn, which means you have to watch even your most cavalier behaviors. Both take a tremendous amount of energy. So evolutionary biologists have to wonder: Why would anyone willingly take on this line of work?
The interview for the job, that single act of sex, is certainly fun. But then you get hired to raise a child. There are wonderful moments, but the essence of the contract is simply: They take. You give. You never get a paycheck with this job, only an invoice, and you’d better be prepared for some sticker shock. You’ll be out more than $220,000—before the college loans. This career comes with no sick days or vacation time, and it puts you permanently on call nights and weekends. Its successful execution will probably turn you into a lifelong worrywart. Yet thousands of people every day say yes to this job. There must be some compelling reason.
Survival, first and foremost
Of course, there is. The brain’s chief job description—yours, mine, and your hopelessly adorable children’s—is to help our bodies survive another day. The reason for survival is as old as Darwin and as young as sexting: so we can project our genes into the next generation. Will a human willingly overcome self-interest to ensure the survival of his or her genes into the next generation? Apparently, yes. Enough of us did hundreds of thousands of years ago that we grew up to take over the Serengeti, then take over the world. Taking care of a baby is a sophisticated way of taking care of ourselves.
But why does it take so much time and effort?
Blame our big, fat, gold-plated, nothing-else-like-it brains. We evolved to have larger brains with higher IQs, which allowed us to move from leopard food to Masters of the Universe in 10 million very short years. We gained big brains through the energy savings of walking on two legs instead of four. But attaining the balance necessary to walk upright required the narrowing of the Homo sapiens pelvic canal. For females, that meant one thing: excruciatingly painful, often fatal births. An arms race quickly developed, evolutionary biologists theorized, between the width of the birth canal and the size of the brain. If the baby’s head were too small, the baby would die (without extraordinary and immediate medical intervention, premature infants wouldn’t last five minutes). If the baby’s head were too big, the mother would die. The solution? Give birth to babies before their skulls become too big to kill mom. The consequence? Kids come into the world before their brains are fully developed. The result? Parenthood.
Because the bun is forced to come out of the oven before it is done, the child needs instruction from veteran brains for years. The relatives are the ones who get the job, as they brought the child into the world in the first place. You don’t have to dig deep into the Darwinian playbook to find a cogent explanation for parenting behavior.
That’s not the entire mystery of parenting, but it underscores its importance. We survived because enough of us became parents good enough to shepherd our pooping, peeing, swearing, breathtakingly vulnerable offspring into adulthood. And we have no real say in the matter. A baby’s brain simply isn’t ready to survive the world.
Clearly, childhood is a vulnerable time. More than a decade passes between the birth of a baby and its ability to reproduce—an eternity compared with other species. This gap shows not only the depth of the brain’s developmental immaturity but also the evolutionary need for unflinchingly attentive parenting. As we evolved, adults who formed protective and continuous teaching relationships with the next generation were at a distinct advantage over those who either could not or would not. In fact, some evolutionary theorists believe that language developed in all its richness just so that this instruction between parent and child could occur with greater depth and efficiency. Relationships among adults were crucial to our survival as well—and they still are, despite ourselves.
We are social beings
Modern society is doing its level best to shred deep social connections. We move constantly. Our relatives are often scattered across hundreds, even thousands, of miles. These days we make and maintain our friendships electronically. One of the chief complaints new parents have in the transition to parenthood is the great isolation they feel from their social circle. To their relatives, baby is often a stranger. To their friends, baby is often a four-letter word. That’s not how it was supposed to be. Take a moment to mark all of
