For children in preschool, speaking two languages may be better than one, especially for developing the skill of inhibitory control, that is, the impulse control necessary to stop a hasty, reflexive response and instead select a more considered, adaptive response.

That idea that bilingual language development in early childhood carries benefits isn’t new, but a University of Oregon study, published in the journal Developmental Science, took a longitudinal approach to examine whether and how the demands associated with managing two languages confer cognitive advantages that extend beyond speaking ability.

“Inhibitory control and executive function are important skills for academic success and positive health outcomes and well-being later in life,” said study co-author, Atika Khurana, of the University of Oregon’s Prevention Science Institute.

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Researchers assessed 1,146 US children enrolled in a national, low-income preschool program for their impulse control at age 4, and then followed the kids over an 18-month period. The kids were divided into three groups based on their language proficiency: Those who spoke only English; those who spoke both Spanish and English; and those who spoke only Spanish at the start of the study but were fluent in both English and Spanish at the six- and 18-month follow-up assessments. Impulse control was assessed using a common pencil-tapping task, in which a child is instructed to tap a pencil on a desk twice when the experimenter taps once, and vice-versa, requiring the student to inhibit the impulse to imitate the experimenter’s actions.

At the beginning of the study, kids who were already bilingual scored higher on the impulse control tests. Over the follow-up period, both the bilingual group and the monolingual-to-bilingual transition group showed more rapid self-control development than the group of English-only speakers.

“The development of inhibitory control occurs rapidly during the preschool years,” said the study’s lead author Jimena Santillán, now a senior research manager at Harvard University’s Center on the Developing Child. “Children with strong inhibitory control are better able to pay attention, follow instructions and take turns. This study shows one way in which environmental influences can impact the development of inhibitory control during younger years.”

Previous studies have examined the benefits of bilingualism on impulse control in children, but have done so with a focus on one point in time or development, and/or have focused on smaller samples from mostly middle-class backgrounds, Santillán said.

“Many studies have addressed the bilingual advantage hypothesis,” she said. “However, the findings have been inconsistent. Part of the reason is the difficulty of randomly assigning participants to be bilingual or monolingual, which would be the ideal research design.”

The longitudinal approach allowed researchers to see how impulse control changed at the same time as bilingual language development in early childhood, as well as to track the change in impulse control for kids who were already bilingual and children who remained monolingual.

“We were able to obtain evidence that bilingualism can be a protective factor that helps children develop these cognitive abilities,” Santillán said. “Provided that more research studies support our results, the findings we’ve obtained could have implications for policies related to bilingual education and could help encourage families to raise their children as bilingual.”