In Courtney Banks' apartment in Chicago's Kenwood neighborhood, Michelle Saenz opens a laptop.
Banks' youngest child, 18-month-old son, Rasean Wright, squirms and flops on his mother's lap.
He's why Saenz is here: to help Banks talk to her son, to build the little boy's brain.
She is part of a project called the Thirty Million Words Initiative, developed at the University of Chicago after researchers found that children in poor households often hear fewer words spoken to them than youngsters in more comfortable families.
Specifically, 30 million fewer words by the age of 3. And the kids who start behind can stay behind once they get to school, contributing to a growing achievement gap between poor and better off students.
So Saenz asks Banks what kind of books she's reading with her son.
"When you trace it all back, really the fundamental thing that grows human brains in the first three years of life is parent talk and interaction. And there is no way around it," says Dana Suskind, a pediatric surgeon at the University of Chicago Hospital and the founder of the Thirty Million Words Initiative. "The brain is hard-wired to learn from human language and interaction."
Suskind conducted close to 200 surgeries to install cochlear implants in the ears of children, to help them hear. Over the years, she came to see first-hand, in the operating room and X-rays, that hearing words vitalizes the brains of infants.
"The language comes in: You get these neural connections building the sort of architecture of the brain. It's really the foundation for all thinking and learning," she says. "I always say that language is the nutrition for the developing brain."
It's not just a question of developing vocabulary, she says: That interaction helps the brain develop to handle things like tying your shoe.
"It's the first three years of life, or the first five years of life, that helps build all of those skills," says Suskind, who has published a book about her initiative that goes by the same same.
She acknowledges there are many reasons why low-income children might hear fewer words.
"It is a complex situation, and certainly families who live in poverty, there are so many stressors that impact a parent's ability to interact with their children. Generally families from lower-income backgrounds, the science shows, don't interact as much.
"But I think that understanding the science allows us to understand why we need social policies that support families in having time with their children, parental leave — those issues are important for helping close the achievement gap."
Some have objected that her program doesn't acknowledge other forms of communication between a parent or child, or how relationships might vary between children and parental figures. Other critics point out that the initiative involves ivory-tower academics telling poor families how to parent.
"My response is ... that keeping the science away from people I would not consider an ethical thing," Suskind says.
And, she says, her program is created in partnership with parents.
"The beauty of the science is that it really demonstrates how powerful parents are. It's not skipping around parents," she says. "I always say, no socioeconomic group has cornered the market on wanting their children to be happy and successful.
Back at Banks' apartment, the mother of five says she looks forward to Saenz's visits.
"I've learned a lot in the few weeks that I have been doing this, and kind of keeping their behaviors under control," she says. "I actually see my youngest kids learning from this experience."
Still, five healthy children are rarely "under control" at the same time. At times, a home visit can resemble a comedy sketch — an earnest academic, trying to get a squirming baby to look at something while the chaos of life goes on around them.
"This is real life. You know, I always say we're looking to not only impact the individual parent, but our ultimate goal is a population-level shift, where this idea isn't about a bunch of University of Chicago academics allowing parents to understand this, but this becomes part of the groundwater.
"And it doesn't happen on one home visit, it doesn't happen with one intervention," she says. "It happens when an idea takes hold in a population."
The idea, in this case, is that the words parents utter to their children have lasting impact.
"Who knew that something that looked so throwaway could be so incredibly powerful?" Suskind asks.
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