silhouette of an adult and a child talkingA number of studies connect underdeveloped language skills in toddlers with attention deficit hyperactivity disorder (ADHD) and with behavioral problems like inattention and hyperactivity. Although the association between language and ADHD is well-attested, a new study investigated whether language development issues or ADHD appear first during in children. Researchers at Indiana University and the University of Virginia find that language skill predicts later ADHD development. The results emphasize the need for early childhood education as a method of reducing social inequality.

This longitudinal study tracked the development of 120 children. The researchers conducted an initial evaluation of the children at age two and assessed the children twice more at ages three and three-and-a-half. They tested the children’s verbal comprehension and spoken vocabulary skills and administered three tests to measure the children’s ability to self-regulate. Parents and secondary caregivers provided their assessments of the children’s behavior as well.

Language skill predicts the growth of children’s self-regulation abilities. Self-regulation predicts children’s capacity to make behavioral adjustments. Children who have less developed language skills are less able to regulate their behavior and more likely to develop behavioral problems like ADHD.

The findings suggest a “developmental cascade” that takes place in early childhood, in which language skills influence many other abilities. Because children from low income families receive less exposure to language than children in more affluent homes, the study’s findings have implications for social inequality.

The authors suggest that the best way to handle this issue is through education. “Children are most likely to acquire skills in language and self-regulation early on. Many of the states are starting to focus on preschool, edging towards universal preschool. But early development specialists are not necessarily available. I would have programs more readily available to families—and focused on children most at risk as early as possible,” explained John Bates, study co-author and professor in the psychological and brain sciences department at Indiana University.

This research is published in the journal Development and Psychology.

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