Children from the poorer strata of society begin life not only with material disadvantages but cognitive ones. Decades of research have confirmed this, including a famous 1995 finding by psychologists Betty Hart and Todd Risley: By age four children reared in poverty have heard 30 million fewer words, on average, than their peers from wealthier families. That gap has been linked to shakier language skills at the start of school, which, in turn, predicts weaker academic performance.
But the sheer quantity of words a toddler hears is not the most significant influence on language acquisition. Growing evidence has led researchers to conclude quality matters more than quantity, and the most valuable quality seems to be back-and-forth communication—what researchers variously call conversational turns, duets or contingent talk.
A paper published last week in Psychological Science brings a new dimension of support to this idea, offering the first evidence these exchanges play a vital role in the development of Broca’s area, the brain region most closely associated with producing speech. Further, the amount of conversational turns a child experiences daily outweighs socioeconomic status in predicting both activity in Broca’s area and the child’s language skills.
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