Various research has shown that multilingualism benefits mental processes in the brain, such as attention, decision-making and executive functioning. Krizman, Marian, Shook, Skoe, & Kraus (2012) found that multilingualism enhances speech perception, attention and working memory. In their study, Spanish-English bilingual high school students and English monolingual high school students were tasked to listen to the speech sound [da] in both quiet and noisy conditions, while their brain activity was measured. It was found that the bilingual students were able to maintain their focus when they heard the speech sound in a noisy environment, as compared to English monolinguals.They also showed enhanced auditory brainstem response to specific sounds in a complex auditory environment.  This suggests that the complex linguistic environment of a bilingual, having grown up with two languages, could have honed his or her ability to be more sensitive in distinguishing sounds. Hence, the attentional abilities of bilinguals would be enhanced.

In addition, multilinguals reportedly have better executive functioning – a system in the brain that helps to control the attentional processes used in daily life, such as in “planning, solving problems and performing various other mentally demanding tasks” (Bhattacharjee, 2012). In a study by Kovács and Mehler (2009), 7-month-old bilingual infants were found to be more adept than monolingual infants at adjusting to “unpredictable rule changes”. Infants were trained to look for pictures of a puppet presented “on the left side of a computer screen” each time they heard an arbitrary trisyllable (e.g., “lo-lo-vu”) (Kovács & Mehler, 2009). Both bilingual and monolingual infants were able to anticipate the puppets by looking at the left hand side of the screen each time the trisyllable sounded. However, when the puppets were presented on the right side of the screen upon the trisyllable sound cue, only the bilingual infants were able to respond accurately by looking at the right side of the screen in subsequent trials, while monolingual infants were unable to do so, continuing to look at the left side of the screen.

Considering the benefits of bilingualism exhibited at a young age even before speech has started, with mere exposure in this study, it is plausible that using more than one language from young would enhance cognitive processes.

Moreover, using another language reduces the tendency of bias in decision making (Keysar, Hayakawa, & An, 2012). According to Keysar, Hayakawa and An (2012), non-native languages, compared to native, create more emotional detachment in participants, opposing the notion that decision-making in another language is less beneficial resulting from increased mental load. Knowing additional languages could allow people to view matters and make decisions more objectively.