In a compelling new study, led by researchers from York University, it has been demonstrated that six-month-old babies raised in a bilingual environment tend to display better attentional control than their monolingual exposed counterparts. The results suggest cognitive benefits from bilingual exposure can manifest before the infants are even capable of speech.

The new research describes two experimental studies conducted with six-month-old infants designed to measure attention and learning. The studies involved tracking the eye movements of the infants while they watched images appear on a screen above them. The experiment works by first establishing a pattern in delivering the images that the infants can quickly identify. When that pattern is disrupted, the infant's attention can be measured by how quickly they recognize the patten change and begin to anticipate where each subsequent new image will appear.

"They will eventually anticipate the picture appearing on the right, for example, by making an eye movement even before that picture appears on the right," explains Scott Adler, co-senior author on the study. "What we found was that the infants who were raised in bilingual environments were able to do this better after the rule is switched than those raised in a monolingual environment."

The implications of the research suggest the potential cognitive benefits of being bilingual transcend the simple ability of switching between two languages. Instead, being raised in a bilingual environment from birth may fundamentally alter the development of neural networks that underly attention.

"What is so ground-breaking about these results, is that they look at infants who are not bilingual yet and who are only hearing the bilingual environment," says Adler. "This is what's having the impact on cognitive performance."

Although the results are undeniably intriguing, the study is small and cannot wholly conclude a causal connection between bilingual environments and the attentional study results. It also comes at a time when there is bitter division among scientists over the purported cognitive benefits of bilingualism.

For much of the second half of the 20th century scientists were relatively confident that bilingualism resulted in a great array of cognitive benefits, primarily concerning improvements to executive function behaviors such as attention and focus. More recently, however, these ideas have been contradicted by a growing body of researchers suggesting those older studies are filled with confirmation bias and false positives.

Kenneth Paap, from San Francisco State University, is at the forefront of bilingual denialism, arguing in an influential 2015 paper that any executive function benefits arising from bilingualism either do not exist or appear, "infrequently and in restricted and undetermined circumstances."

This new study from York University may add a little weight to the bilingual benefits argument but it by no means settles this relatively new scientific debate. However, we can be confident that there are most likely no harmful negatives associated with bilingualism, unlike those suggested by a Cambridge University professor in 1890, who once wrote, "If it were possible for a child to live in two languages at once equally well, so much the worse. His intellectual and spiritual growth would not thereby be doubled, but halved. Unity of mind and character would have great difficulty in asserting itself in such circumstances."

The new study was published in the journal Developmental Science.