The adaptations that children gain from growing up in a bilingual household appear to provide cognitive benefits that carry over well into adulthood, a new study has found.

The research is the first to demonstrate that adults who are considered “early bilinguals,” or those who acquired their second language as an infant or a young child, are more nimble in detecting visual changes and shifting their attention accordingly, compared to those who are “late bilinguals,” who learned their second language later on in life.

The study, published Jan. 22 in Scientific Reports, used eye-tracking experiments to collect data from 127 adults, testing their ability to disengage attention, meaning to stop giving something attention, to switch attention between two different stimuli and to notice changes. These experiments highlighted how early bilinguals were noticeably faster at noticing changes in images and at disengaging their attention than the late bilinguals were.

This investigation stemmed from earlier research conducted by the research team that was focused on how infants adapt to their environment, according to Dean D’Souza, a senior lecturer at Anglia Ruskin University in the U.K. and an author of the study.

“Some children are hearing just one language in their environment, which is a very simple, basic environment,” D’Souza said. “Other children are hearing lots of different languages, and maybe lots of different languages from one person, let alone from two or more people. For me, my interests lie in how these infants adapt to their more complex environments.”

Earlier studies had shown that infants indeed show various adaptations to differences in their language environment, D’Souza said, but the fact that this follow-up study demonstrated the lingering effects of those adaptations well into adulthood came as “a complete surprise.” 

The cognitive benefits of these adaptations are still being investigated, though D’Souza said that for infants, growing up in a bilingual home may facilitate a greater understanding of language skills.

“Infants who hear two or more languages, who are exposed to more varied and less predictable language, have benefits over those who only hear one language,” D’Souza said. “Those infants may have their attention driven more widely and be attracted to more varied inputs, such as mouth movement, spatial expression, subtle gestures — and may be linking these to what they’re hearing to facilitate their language learning.”

As for the implications of these benefits in adulthood, that’s a question that still needs to be answered, D’Souza said, adding that the researchers would have to follow these adults in a more natural or everyday environment to observe any potential changes.

“What we found was that the bilingual adults were able to disengage their attention quicker in order to shift it, and they were able to detect changes quicker. These were the adults who acquired their second language early in life,” D’Souza said. “But of course, we don’t know the real-world implications for that for adults. We would have to study them in their actual environment.”

However, the findings from this study are promising and encourage further research by showing that adaptations gained in infancy among early bilinguals do indeed persist into adulthood, D’Souza added, noting that this is just one of several potential next steps for this line of investigation.

“We would like to look at changes that occur in the level of the brains,” D’Souza said. “Do changes that occur in the level of the brain as infants, are these maintained into adulthood? We want to look at other levels, as well as look as the infants and adults in their naturalistic environment so we can draw more firmer conclusions that could be practical to adults.”

The study, “Early bilingual experience is associated with change detection ability in adults,” was published on Jan. 22, 2021 in Scientific Reports. It was authored by Dean D’Souza of Anglia Ruskin University, Daniel Brady of the University of Reading, Jennifer Haensel of the Stanford University School of Medicine, and Hana D’Souza of the University of Cambridge.