Why just one word can alter how the brain processes information

In practice, the gulf of understanding between a fact and a possibility can be huge. It’s the difference between knowing we do have safe and effective coronavirus vaccines, and thinking that we might have them.

But in language, the difference between a fact and a possibility is small. Just insert one or two words, and something set in stone becomes hazy. According to new research, just adding a collection of syllables to a phrase can make the brain react to that information in a totally different way.

Accordingly, the brain reacts more strongly to factual statements than it does to statements that convey uncertainty, according to research published Monday in the journal ENeuro.

Factual statements that have strong, certain verbs like “do” encourage the brain to update its model of the current situation with cold, hard facts. If you hear the phrase: "Superheroes wear masks, so their sidekicks do too," the brain only has to entertain one reality — that sidekicks also wear masks. However, the phrase “Superheroes wear masks, so their sidekicks may too” is the catalyst for a new situation. The brain has to entertain two realities: one where sidekicks wear masks and one where they don’t.

Maxime Tulling is the study’s first author and a Ph.D. student in linguistics at New York University. She tells Inverse that the brain shows a more powerful response when exposed to a more cut-and-dry situation.

“Information presented as fact immediately evokes special responses in our brains, distinct from when we process the same information with clear markers of uncertainty, like ‘may’ or ‘might’,” Tulling says.

However, including words like "might" or "may" can switch the brain from fact-mode to uncertainty-mode.

“Language is a powerful device to effectively transmit information, and the way in which information is presented has direct consequences for how our brains process it,” she continues.

"The way in which information is presented has direct consequences for how our brains process it."

How the brain processes factual language – The study is based on measurements of electrical brain activity taken from 26 adults who participated in two experiments. In one of the experiments, the adults silently read stories that either contained a factual statement with the verb “do” or modal verbs like “might” or “may” which introduce uncertainty.

For example, the sentences might read:

Knights own many weapons, so their squires do too.

Knights carry heavy armor, so their squires might too.

When people read sentences that conveyed factual information, the team found the most powerful responses in the brain’s right temporoparietal junction – an area between the parietal, and temporal lobe.

Perspective seemed to change the epicenter of activity. When the fact required updating our own beliefs, the activity was located in near the front of the brain. When it required updating someone else's beliefs, it was centered on the right side.

This response happened quickly, which suggests that “our brains rapidly distinguish facts from possibilities," Tulling explains.

Why does this happen? Tulling reasons that when the brain encounters factual information it can rapidly update its understanding of the situation before we've even comprehended it — triggering strong brain activity. But when we encounter uncertain information, the brain has a more complicated task ahead of it:

“[When] we encounter the verb ‘may,’ we recognize the possibility that the sidekicks wear masks but have no certainty about whether or not this is actually the case. The brain seems immediately sensitive to this contrast, putting this uncertain information on hold.”

Importantly, it’s not the words themselves that matter that much, Tulling says. As long as the sentence conveys uncertainty, the brain will treat it differently.

The bigger picture – Factual language is simple: A superhero sidekick wears a mask or he does not. But our understanding and internalization of facts is far more complicated.

Simply put, people often selectively seek out information that confirms their existing beliefs rather than expose themselves to facts that might undermine them. And though facts can help us update our understanding of a situation, we don’t always use facts to update our understandings of bigger ideas —which is why facts about safety don’t always convince people to get vaccinated, for example.

This study can’t answer the big picture questions about why facts don’t always hit home. But it does demonstrate the power of using factual language to convey information. If you do, you might ignite distinct and powerful responses in the brain.

In light of the coronavirus pandemic, there are examples of statements that feel especially powerful: think of a factual statement like “masks work.” But the messaging on masks was, at least at first, not very clear. In April, for example, the CDC recommended Americans wear cloth face coverings, describing the action as a "voluntary public health measure." In December, the CDC advocated, for the first time, "universal use of face masks." The language has changed — and perhaps, so might understanding.

At least when dealing with simple situations in the here and now, uncertain language doesn’t hit the brain as hard. Whether uncertain language affects how we internalize more complicated and abstract ideas, like the utility of masks, is unclear.

“That is an interesting question that we do not have an answer for right now,” Tulling says.

The first step to answering that question to dig into how the brain processes not just facts, but grey areas. This study shows that the brain may react more strongly to factual information, and less intensely to words that convey uncertainty, but there could be other patterns hidden beneath the surface that this study missed.

“In future research, we hope to learn more about the neural representation of possibilities,” Tulling says.

Abstract:

A hallmark of human thought is the ability to think about not just the actual world, but also about alternative ways the world could be. One way to study this contrast is through language. Language has grammatical devices for expressing possibilities and necessities, such as the words might or must. With these devices, called "modal expressions," we can study the actual vs. possible contrast in a highly controlled way. While factual utterances such as “There is a monster under my bed” update the here-and-now of a discourse model, a modal version of this sentence, "There might be a monster under my bed,” displaces from the here-and-now and merely postulates a possibility. We used magnetoencephalography (MEG) to test whether the processes of discourse updating and modal displacement dissociate in the brain. Factual and modal utterances were embedded in short narratives, and across two experiments, factual expressions increased the measured activity over modal expressions. However, the localization of the increase appeared to depend on perspective: signal localizing in right temporo-parietal areas increased when updating the representation of someone else’s beliefs, while frontal medial areas seem sensitive to updating one’s own beliefs. The presence of modal displacement did not elevate MEG signal strength in any of our analyses. In sum, this study identifies potential neural signatures of the process by which facts get added to our mental representation of the world.