Making sense of our words

Information presented as fact evokes a stronger response in our brains than when it contains words that convey uncertainty, such as may, must or might, according to a study published in the journal eNeuro.

“Language matters,” says lead author Maxime Tulling from New York University, US. “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.”

Unlike other animals, our language allows us to talk about things beyond the immediate present. “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,” write Tulling and colleagues.

We could say, for instance, “there is a monster under the bed” or “there might be a monster under the bed.” The latter statement, a “modal expression”, is more ambiguous – either there’s a monster or there isn’t.

“Processing possibility utterances thus requires keeping multiple possibilities in mind, because there is uncertainty about which option is applicable to the actual situation,” Tulling explains. “On the other hand, factual utterances do provide you with this certainty: you can update your knowledge about a situation by incorporating the newly learned information.”

That doesn’t mean we necessarily believe the scenarios our brains represent when presented with facts: rather it paints a mental picture of the situation, whether true or not.

If you hear “pigs are flying in the sky”, for instance, you can imagine this without having to believe that pigs can fly. When you hear the possible scenario “pigs might be flying in the sky”, you could also paint a mental picture, but it’s not clear if pigs are there or not.

“The reason we think the brain is more responsive to factual language is because the painted mental picture is more detailed and clearer, you are committed to the pigs,” Tulling says. “Your representation of a possibility seems to be more elusive – you might think of fuzzy pigs or maybe err on the safe side and don’t paint the pigs at all.”

The researchers used magnetoencephalography (MEG), a non-invasive technology that maps brain activity by measuring magnetic fields produced by its electrical currents, in two experiments with 26 adult volunteers.

While lying in the machine, participants read a series of short narratives and answered questions about them. These contained scenarios such as “Superheroes wear masks” continued by a factual statement, such as “so their sidekicks do too”, or a possibility statement, “so their sidekicks may too”.

Results showed that certain regions of participants’ brains had rapid and powerful responses to being presented with facts compared to possibilities.

Importantly, this had nothing to do with inherent differences between the verbs, Tulling notes. The second experiment included an uncertain base statement in each scenario, such as “If superheroes wear masks”, confirming that it didn’t matter if the continuing statement contained “do” or “may” as the entire sentence was based on a possibility.

Results also found that where this phenomenon occurred in the brain depended on perspective. When facts were considered from someone else’s point of view, right lateral areas responded. Considering it from one’s own perspective evoked frontal medial brain areas.

The researchers say this is the first study to show that the brain responds differently to facts and hypotheticals, and there is more to learn. “By identifying the neural correlates of updating discourse representations, we pave the way for future research on the processing and representation of non-factual discourse.”