Income inequality has been talked about a lot during this election cycle—whether it's in the context of breaking up big banks, regulating Wall Street (or giving speeches to big banks on Wall Street) or lamenting the way trade deals have bled the middle and working classes dry. But political scientist Robert Putnam, in his book "Our Kids: The American Dream In Crisis," looks at another angle: the way income inequality is trickling down to our public education system.

Putnam points out that Americans of different classes and educational backgrounds are increasingly living apart from each other: either in educated, wealthy enclaves or the inverse. That has a negative and stratifying effect on schools, particularly on schools in poor areas.

"What we know very well is that when rich kids go to school, in their backpack they bring their parents' aspirations, their parents' resources, their parents' trips to France, their allusions to Proust or whatever, and that benefits all the kids in town," Putnam said.

Because our worlds...become so separate, we don't have any firsthand appreciation of what life is like on the other side of tracks.

"When poor kids go to school, they're bringing in their backpack gang violence—even if they're not personally involved—they're coming from very poor neighborhoods, they bring disarray from home, hunger at home, and those factors affect everyone else," he continued.

What he found shocking, too, over the course of his research was how much this stratification prevented wealthier families and students from being able to see and to relate to poverty in their own communities. He described an encounter with a young man from Bend, Oregon who told Putnam there were no poor people in his community—despite that being far from true.

"I thought, this is how America has become so segregated that this guy—who was a nice kid, I'm not ragging on him—but he was living just five minutes away from intense poverty," Putnam said. "But because our worlds—and I mean our worlds, too, in the Boston area—become so separate we don't have any firsthand appreciation of what life is like on the other side of tracks."

Robert Putnam is Peter and Isabel Malkin Professor of Public Policy at Harvard and the author, most recently, of "Our Kids: The American Dream In Crisis." To hear more from Putnam, tune in to Boston Public Radio above.