The Winners and Losers in Childhood Development
In a 2013 study at Stanford University, 48 infants of diverse economic socioeconomic status (SES) were tracked from 18 - 24 months of age and measured in language proficiency. Researchers found that at 18 months, children of higher SES were already significantly better off in vocabulary and language processing efficiency, and by 24 months, there developed "a 6-month gap between SES groups in processing skills critical to language development" (Fernald 2013).
This could easily be linked to the 1995 Hart and Risley Study, which found that children from professional families heard a significantly greater quantity of words per hour on average (2153 words) than those from working class (1251) or welfare-recipient (616) families, leading to the former having larger vocabularies. (Hart 1995). They reach the stark conclusion that the "most important aspect of children's language experience is quantity", though they note that children in professional families were encouraged more and discouraged less than their counterparts in less well-off families.
This gap is not just in vocabulary. According to an article published in Psychophysiology, "SES disparities in neurocognitive functioning have been shown across the domains of language, EF, memory, and social-emotional processing on both the behavioral and neurobiological levels" (Ursache 2017). They note a couple possibilities why these disparities could exist. As previously mentioned, language stimulation is a major distinction between households of different SES. In addition, the stresses of poverty could lead to "inconsistent, unpredictable, and non responsive parenting behaviors", harming emotional development, and also lead to less time and energy being spent on supportive parenting.
Even though educational systems cannot solve the root issue of socioeconomic disparity, our preliminary understanding still points towards certain behaviors that would help solve the problem. In the classroom, educators can introduce more new words in their day to day speech as well as help parents to do the same (Colker 2014). Attention needs to be paid towards consistency and responsiveness in educator-child interactions, especially if these qualities are lacking in those of the parent and child.