It was once believed that trying to learn more than one language at a time would be too confusing for small children.

“Once upon a time, we also believed that the world was flat,” says Dr Mariano Sigman, neuroscientist and author of a new book about the mysteries of the brain, in an interview with the World Economic Forum.

His book, The Secret Life of the Mind, dispenses with this myth and explores, among other things, the enhanced cognitive ability of bilingual children.

Sigman claims that babies who grow up bilingual have brain functions that are superior to those of monolingual children, because they have better “cognitive control”.

“Cognitive control has many aspects,” he explains. “Such as the ability to pay attention, the ability to plan and the ability to switch easily between tasks.

“One of the things most studied about bilingualism is this task-switching, and bilingual children consistently (outperform) monolingual children in this regard,” he says.

The same is true of adults, and experiments highlighted by Sigman in his book shed light on why this happens.

“There have been experiments in adults where their brain activity has been measured during switching between tasks.

“In one study, participants saw a sequence of objects flashing rapidly in the centre of a screen. They were asked to respond with a button if the object was red, and with another button if it was blue. Then, suddenly, participants were asked to forget about colour and respond using the same buttons about the shape of the object.

“Bilinguals tended to switch between the two responses faster than monolinguals,” says Sigman.

“When their brain activity was measured, it showed that they were using the language network in their brain. In other words, their brain’s ability to switch between languages came in useful for other types of tasks.”

Why is cognitive control so important?

“Many studies undertaken on vulnerable children show that the likelihood of them doing well in society from an economic perspective is closely related to cognitive control,” explains Sigman.

“In many countries, there are government interventions that target cognitive control, things like attention, flexibility and planning. The ability to wait patiently for something, not rushing into immediate satisfaction; being in control of your mind.

“People who have good cognitive control do well at school, typically find better jobs and are healthier. They have better social insertion,” he says.

Myths about bilingualism

That children might be confused when learning two languages at once is not the only myth, according to Sigman.

“One myth of bilingualism is that different people should be consistent in speaking only one language, so for instance, a French mother should only speak French to her child; or the child should only speak Spanish in school and English at home.

“But this isn’t true. Babies are very good at picking facial cues to tell them what language people are speaking. What this means is that babies become very good at understanding context.

Is bilingual better?

Countless studies have argued the case for bilingualism.

It helps children become more empathetic, because they can see things from a different perspective than their own.

For example, in one study, an adult asked a child to pass them a small toy car.

There were three toy cars – small, medium and large – but the adult could only see the medium and large ones. Bilingual children were more likely to choose the medium-sized car, because they knew the adult couldn’t see the smallest.

This study also found that children didn’t have to be bilingual to perform better in the test: being exposed to another language was enough.

Research suggests that being able to speak more than one language could also hold back the onset of Alzheimer’s.

Bilinguals even experience time differently, and it can help children become accustomed to diversity and different cultures.

“Perhaps we should promote bilingualism,” concludes Sigman.

“Amid so many less effective and more costly methods of stimulating cognitive development, this is a much simpler, more beautiful and enduring way to do so.”

Sigman adds a note of caution: “Bilingual experiments are hard to do, as it’s hard to control for other variables, such as cultural differences.

“While being bilingual seems to be a good way of keeping the mind healthy, it doesn’t automatically mean that you won’t get dementia, or even that you will have good cognitive control. Bilingual is certainly a factor that contributes, but it sits among many other factors.”

In other words, the brain is notoriously complex and enigmatic.

“We are very far from understanding the full workings of the brain,” he adds. “It’s like the universe: the more we learn the more we understand that there is so much more to learn.”