Shopping at a local gift shop, I overheard a young mother speak to her toddler with the precise diction of an English professor: "I want to meander a little longer. Will you meander with me? Then, we'll get a delectable snack."

Later that week, I walked behind another young mom and toddler leaving a grocery store. The little girl clutched an empty candy wrapper in her hand. “Take this, mama,” she said, offering the trash to her mother. “That’s nasty,” the woman told her. “Throw it on the ground.”

Both those kids will arrive in kindergarten around the same time, one primed with SAT vocabulary words, the other trained to litter.

Somehow, schools are supposed to propel these students to the same finish line, ready to take their place in an increasingly complex world where advanced literacy and math skills are imperatives.

In a recent webcast on high school graduation rates, Robert Putnam, author of “Bowling Alone” and the new book “Our Kids,” discussed the graduation gap between rich and poor kids — a gap driven, he says, more by social class than race.

“Kids are getting better and better coming from college-educated homes. Things are getting worse and worse for poor kids, kids coming from what we used to call the working class,” said Putnam, a professor of public policy at Harvard. Putnam cites the disparity in what he calls “Goodnight Moon” time, referencing the beloved bedtime story as a representation of the hours educated parents devote to their children.

There used to be no difference in the amount of time rich and poor parents spent reading to their kids. Now, Putnam says, “My granddaughter gets 45 minutes a day more reading time with mom and dad than equally smart kids from the working class. We know now from recent brain science that the architecture of the infant brain changes where there is adult-child interaction. There is a growing gap in those kids living in circumstances where the parents don’t or can’t spend that time reading, a growing gap in ‘Goodnight Moon’ time.”

A few weeks ago, I went with my daughter, the mother of an 8-month-old, to a Mother’s Day celebration at a local community center that specializes in classes for new moms. After meeting young mothers who take their infants to baby sign language and yoga classes and listening to their discussions of breast pumps, homemade baby food and educational toys, I was convinced they were raising a super race.

We chortle over the intense focus of young parents on their children’s development, seeing them as overly attentive and hovering. We shake our heads over Park Avenue parents who pay $35,000 for top Manhattan preschools that teach 3-year-olds Mandarin. But emerging research shows such investments of time, energy and money in these tiny humans produce immense returns in school readiness and success.

The differences in good and bad schools today is less about what schools do than what students bring to school, argues Putnam. Children of educated households bring a bounty of parental involvement, expectations and resources. Poor kids bring liabilities, including economic pressures, family dysfunction and distracted parents.

More than 90 percent of children in college-educated homes are being raised by two parents, says Putnam, compared with 30 percent of children from high school-educated homes. His concern is not moral, but practical. One parent can do less for a child than two parents.

Smart, poor kids with high test scores are now less likely to graduate from college than not-so-smart rich kids with low test scores, exactly the opposite of what the American dream used to be, says Putnam,

“Your chances in life shouldn’t depend on your parents,” he says. “They should depend on you.”