Although decades of research have established a relationship between socioeconomic status and children's brain development, the specifics of this connection are not known. The so-called "word gap" -- the influential finding from the early 1990s that school-age children who grew up in lower-SES households have heard 30 million fewer words than their more affluent classmates -- and other evidence demonstrating an influence of early language exposure on later language ability suggests a potential influence of language experience on brain structure.

In their neuroimaging study of 40 four- to six-year-old children and their parents of diverse socioeconomic backgrounds, Rachel Romeo and colleagues found that greater conversational turn-taking (measured over a weekend with an in-home audio recording device) was related to stronger connections between Wernicke's area and Broca's area -- brain regions critical for the comprehension and production of speech.