July 27, 2021
Written by: Catrina Hacker
Effectively communicating through speech is a challenging task. It requires us to articulate our thoughts in a manner that will reproduce the same thoughts in the listener’s head. Every time we go from thoughts to words and from words to thoughts there is an opportunity for information to be lost or jumbled. Sometimes conversations are awkward and we feel like we’re not on the same page as our partners. Other times conversation is so easy that we feel we could talk to the same person for hours. What is happening differently in our brains when conversations click versus when they don’t?
To address this question, neuroscientists at Princeton University imaged the brains of two people as one spoke and the other listened1. To do this, they had one person come into the lab and tell a story about their life as the researchers measured their brain activity. Later, the researchers invited a second person to the lab and measured their brain activity while they listened to a recording of the first person telling the story. Afterward the researchers quizzed the listener on the story to determine how much they understood. The researchers found that the more the listeners understood the story, the more their neural activity matched that of the speakers, both in terms of what brain areas were active and when they were active. In other words, effective communication occurred when the speaker’s brain activity was reproduced in the listener’s brain.
In a follow-up study, the research group wanted to know if the similarity in brain activity they had observed was because of the words used to communicate the story or because of the content of the story. They wondered if the ideas of a story are represented the same way in the brain regardless of the language that the story is told in. To test this, they looked at the brain activity of native English speakers hearing the story in English versus that of native Russian speakers hearing the same story in Russian2. First, they showed that there was a strong similarity in the brain activity of speakers and listeners for English speakers listening to the story in English and Russian speakers listening to the story in Russian. Interestingly, they found that the similarity of brain activity between language groups was almost as high as the similarity of brain activity within language groups. That is to say, the brain activity of the Russian listeners was almost as similar to the brain activity of English listeners as it was to the brain activity of other Russian speakers. This suggests that the human brain processes the content of a story almost the same way regardless of what language it is told in, and that similarities in brain activity have to do with communication of content and not the language used to communicate it.
Recently, the same group wondered whether their findings about the similarity of brain activity being related to comprehension could also predict which students were likely to do best on an exam. They hypothesized that students who understood the course material best would show brain activity that was most similar to experts when taking a test. To test this, they recorded the brain activity of students who were enrolled in a computer science class over the course of several weeks3. At the end of the course, they recorded the students’ brain activity as they watched a video reviewing the material from the course and took a final exam. They also recorded the brain activity of graduate student experts viewing the same review video and taking the same exam. The researchers found that students performed better on test questions when their brain activity matched that of experts than on questions when their brain activity was very different than experts. In other words, how similar the brain activity of the student was to an expert could predict how well the student had learned that material.
The goal of speaking is to choose words that capture our own thoughts and to convey them to another person. Together, these studies show that successful communication results when those words produce similar brain activity in the listener as was present in the speaker. Whether we’re speaking in English or Russian, telling stories or giving lectures, ultimately the goal is to get in sync.
1. Stephens, G. J., Silbert, L. J. & Hasson, U. Speaker-listener neural coupling underlies successful communication.Proc. Natl. Acad. Sci. 107, 14425–14430 (2010).
2. Honey, C. J., Thompson, C. R., Lerner, Y. & Hasson, U. Not Lost in Translation: Neural Responses Shared Across Languages. J. Neurosci. 32, 15277–15283 (2012).
3. Meshulam, M. et al. Neural alignment predicts learning outcomes in students taking an introduction to computer science course. Nat. Commun. 12, 1922 (2021).