…In work they conducted at the University of Kansas and chronicled in their book Meaningful Differences in the Everyday Experience of Young American Children, Betty Hart and Todd Risley recorded, for two-and-a-half years, a full hour of conversation every day between parents and children from 42 American families of differing social classes. Children with professional parents heard about 30 million words by the time they turned 3, compared with 20 million in working-class families and 10 million in welfare families. In addition, the ratio of parental encouragements to reprimands was about 6-to-1 among professional families, 2-to-1 among the working class and 1-to-2 in welfare homes. These different experiences closely tracked with the children’s later academic and intellectual performance, and otherstudieshave since supported these findings.

But what does all this have to do with preschool? Research suggests that preschool only benefits children from these disadvantaged families (in particular, families that arebelow the poverty line, whosemothers are uneducated, or who areracial minorities). This could be because preschool acts as a kind of “equalizer,” ensuring that for at least a few hours a day, these kids get the same high-quality interaction with adults as more advantaged children do, which helps to even the developmental playing field.

For instance, in astudypublished last year, University of Texas psychologist Elliot Tucker-Drob assessed a number of different characteristics in a group of more than 600 pairs of twins. He looked at the scores the children got at age 2 on tests of mental ability; whether or not they went to preschool; how “stimulating” their mothers’ interactions were with them; their socio-economic status and race; and finally, how well they scored on reading and math tests at age 5. Because he was comparing what happened to identical twins, who share all of their genes, and fraternal twins, who on average share half (yet both sets typically grow up together), Tucker-Drob could home in on the effects of environment and genetics on the kids’ outcomes.

A hell of a lot of math later, Tucker-Drob reported that the home environments of children who do not attend preschool have a much larger influence on kindergarten academic ability than do the home environments of preschoolers. In other words, a bad home situation becomes a much smaller problem when your kid goes to preschool; when you have a good home environment, preschool doesn’t really matter. (Granted, children from poor families tend to go to lower quality preschools than wealthy kids do, but for them, a bad preschool is usually better than nothing.)How important is preschool? If you are researching early education philosophies, not very. – Slate Magazine.