The Benefits of Multilingualism by Jared Diamond

“Our minds are assaulted by varied sights, sounds, and other external sensory inputs, plus thoughts and proprioreceptive sensations (which make us aware of the relative positions of our own body parts) (see the figure). To succeed in doing anything at all, we must temporarily inhibit 99% of those inputs and attend to just 1% of them, and the appropriate choice varies with the circumstances. That selective attention involves a set of processes, termed executive function, that reside in the prefrontal cortex and develop especially over the first 5 years of life (9)
[…] As a result, multilinguals have constant unconscious practice in using the executive function system.”

Source: The Benefits of Multilingualism by Jared Diamond | ScienceMag.org