The beauty of those kinds of parenting activities is that they don’t cost much, if any, money. The problem is that low-income parents still lag behind their more affluent peers when it comes to engaging in those behaviors. Economically disadvantaged parents, research shows, still spend far less time than their middle-class counterparts participating in developmentally stimulating activities with their children.

A recent study published by the American Educational Research Association aimed to get a better sense of how those income-based differences in parenting behaviors have evolved over time, drawing data from four nationally representative, longitudinal surveys conducted between 1988 and 2012. The research findings are promising in that they show lower-income parents are engaging in activities like reading and educational excursions more than ever before. But they also show that, for six of the eight behaviors studied, the disparities only grew.

“In one sense, [disadvantaged parents] have really caught up; in another sense, they’re two decades behind,” said Ariel Kalil, the study’s lead author and a professor in the University of Chicago’s Harris School of Public Policy Studies. “It’s an interesting puzzle because you could say this is great news, but on the other hand there are still these gaping inequalities in what [educational experiences] children are getting across different kinds of families.”

Parenting Activities That Saw Growing Income-Based Gaps (1988-2012)

Parenting Activities That Saw a Marked Increase Among Those at the Median Income Level (1988-2012)

The reason the gaps grew is simply because affluent, college-educated parents engaged in those behaviors “at a much higher level of intensity,” Kalil said. In other words, after gaining access to new brain science and discovering that things like trips to the museum and storytelling before bedtime are vital to helping a young child’s brain develop and preparing her for success in school, parents with means started doing them at unprecedented (and, arguably, even excessive) levels. Poorer, less-educated parents got wind of that insight, too, and likewise started ramping up the degree to which they fostered their children’s development. They just weren’t able to catch up.

“It’s basically just this kind of ratcheting up of competition,” said Kalil, a developmental psychologist who co-directs the University of Chicago’s Behavioral Insights and Parenting Lab. “It’s high-income parents consuming the literature on the importance of brain development, the sensitivity of the early-childhood years. It’s them consuming that information and responding to it more quickly” than their less-fortunate counterparts.