As the presidential candidates argue over how to strengthen America, maybe they can learn from rats.
A McGill University neurologist, Michael Meaney, noticed that some of the mother rats he worked with spent a great deal of time licking and grooming their babies. Other rat moms were much less cuddly.
This natural variation had long-term consequences. Dr. Meaney's team found that when the rats grew up, those that had been licked and groomed did better at finding their way through mazes.
They were more social and curious. They even lived longer.
Dr. Meaney's team dissected adult rats and found that licking led to differences in brain anatomy, so that rats that had been licked more were better able to control stress responses.
So, could the human version of licking and grooming -- hugging and kissing babies, and reading to them -- fortify our offspring and even our society as well?
One University of Minnesota study that began in the 1970s followed 267 children of first-time low-income mothers for nearly four decades. It found that whether a child received supportive parenting in the first few years of life was at least as good a predictor as IQ of whether he or she would graduate from high school.
This may illuminate one way that poverty replicates itself from generation to generation. Children in poor households grow up under constant stress, disproportionately raised by young, single mothers also under tremendous stress, and the result may be brain architecture that makes it harder for the children to thrive at school or succeed in the work force.
Yet the cycle can be broken, and the implication is that the most cost-effective way to address poverty isn't necessarily housing vouchers or welfare initiatives or prison-building. Rather, it may be early childhood education and parenting programs.
Scholars like James Heckman of the University of Chicago and Dr. Jack Shonkoff of Harvard have pioneered this field, and decades of fascinating research is now wonderfully assembled in Paul Tough's important new book, "How Children Succeed." Long may this book dwell on the best-seller lists!
As Mr. Tough suggests, the evidence is mounting that conservatives are right about some fundamental issues relating to poverty. For starters, we can't talk just about welfare or tax policy but must also consider culture and character.
"There is no anti-poverty tool we can provide for disadvantaged young people that will be more valuable," Mr. Tough writes, than grit, resilience, perseverance and optimism.
Yet conservatives sometimes mistakenly see that as the end of the conversation.
"This science suggests a very different reality," Mr. Tough writes. "It says that the character strengths that matter so much to young people's success are not innate; they don't appear in us magically, as a result of good luck or good genes. And they are not simply a choice. They are rooted in brain chemistry, and they are molded, in measurable and predictable ways, by the environment in which kids grow up. That means the rest of us -- society as a whole -- can do an enormous amount to influence their development."
Here's an example: the Nurse-Family Partnership, one of my favorite groups fighting poverty in America. It sends nurses on regular visits to at-risk first-time moms, from pregnancy until the child turns 2. The nurses warn about alcohol or drug abuse and encourage habits of attentive parenting, like reading to the child. The results are stunning: At age 15, these children are less than half as likely to have been arrested as kids from similar circumstances who were not enrolled.
Maybe we're beginning to crack the code of how to chip away at so many of America's domestic problems. Mr. Tough cites evidence that while toxic stress or unsupportive parenting damages the prefrontal cortex in infancy, this damage can often be undone at least through adolescence.
He tells the story of Kewauna Lerma, a girl from Chicago who started high school with a C- average and an arrest. Then a group called OneGoal, which has emerged out of this wave of research, began to work with Kewauna and nurtured her ambitions and talents.
President Barack Obama and Mitt Romney, listen up: Kewauna's story underscores that strengthening our nation means investing not only in warships but also in America's children.
On a practice ACT standardized test, Kewauna scored in the bottom 1 percentile. Yet she began to focus on schoolwork, and her grades and test results soared. In her senior year of high school, she didn't have a grade lower than an A-.
She made it to college, where her toughest class was biology and the professor used words that Kewauna didn't understand. So she sat in the front row and after class asked the professor what each word meant. Kewauna was short on money, and once when she ran out of cash she didn't eat for two days. But in biology, she earned an A+.opinion_commentary
Nicholas D. Kristof is a syndicated columnist for The New York Times.