Speaking two languages doesn't just expand your ability to communicate globally.

It can make you more rational, improve your decision-making skills and boost your memory, says University of Chicago psychology professor David Gallo.

"Having a lifetime experience in switching between languages exercises your brain in a way that monolinguals don't get," Gallo, the director of UChicago's Memory Research Laboratory, tells CNBC Make It. "Monolinguals don't develop as rich [mental] connections, and the ability to switch on and off different mental states."

Gallo's current work focuses on how speaking multiple languages can affect your cognition. Along with fellow UChicago psychology professor Boaz Keysar, he found something potentially counterintuitive: When you process information in your secondary language, you make more rational and logical decisions.

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That finding also applies to critical thinking and memory, both of which are crucial skills in life and the workplace. Critical thinking, for example, is one of the top three traits that employers want but job applicants lack, according to recent ZipRecruiter data.

Conventional wisdom says you might struggle to make decisions in a language where you have less experience and vocabulary. Here's why it works anyway, according to Gallo.

Your second language presents a brain shortcut

Speaking in your native language is easy — and it can lull your brain into being less able to process information objectively, says Gallo.

Your emotions start to impede your rationality, speeding up your decision-making but making you more prone to mistakes, Gallo says. When that happens, you're stuck in a mindset Gallo refers to as "hot cognition," also known as "System 1 thinking."

Gallo likens the opposite mindset — cold cognition, or System 2 thinking — to the character of Spock from "Star Trek."

"He shuts off all of his emotions to try to be as logical and analytical as possible," Gallo says.

Such a mindset makes you more strategic, deliberate and careful, leading to fewer mistakes, he says — though it does mean you'll take longer to make decisions.

"When you are thinking in your second language, you are being very analytical and careful about the surface-level features of information," he explains. "And that, in turn, might put you in this mindset where you're being more logical and rational when approaching decision-making tasks."

Both mindsets are useful. You need hot cognition to make quick, split-second decisions, and cold cognition comes in handy in times of crisis or risk.

The problem: It can be tough to force your brain to think rationally when emotions are running high. Using your second language acts as a quick shortcut into "Spock mode," Gallo says.

It can help you avoid false memories and misinformation

The benefits of a second language extend beyond analytical thinking, says Gallo. People are more susceptible to misinformation and false memories — remembering something inaccurately, or something that never happened at all — when thinking in their native language, Gallo and Keysar's research found in July.

The effect was so strong that the ability to talk in a foreign language "completely eliminated" false memories, Gallo says.

The finding centers around a psychological concept called "memory monitoring," which is how your brain determines whether a memory actually happened or your brain made it up. Memory is somewhat malleable: Your feelings during an event can shift how you remember it afterward, for example.

"It's not just that you are better able to monitor your memory [when using your second language] but it seems like you're being so analytical that you're not even fooled by that misinformation anymore," says Gallo.

Speaking multiple languages can also enhance communication in the workplace, increase productivity and improve concentration, suggests a 2019 survey from language software company Rosetta Stone.

How to leverage the shortcut most effectively

Speaking multiple languages doesn't inherently make someone more rational, Gallo cautions. And if you aren't fluent in your second language, you can miss critical information or slow down your decision-making speed.

But when you're trying to make a tough decision, or remember a piece of information, try thinking about it in a different language, Gallo recommends.

If you don't know multiple languages, his advice is simpler: Learn a new one. Encourage your kids to grow up learning multiple languages, too. Within older adults, bilinguals may fare better than monolinguals against aging-related cognitive decline, says Gallo.

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