Researchers from MIT have been using a language processing AI to study what type of phrases trigger activity in the brain’s language processing areas. They found that complex sentences requiring decoding or unfamiliar words triggered higher responses in these areas than simple or nonsensical sentences. The AI was trained on 1,000 sentences from diverse sources, and its responses were compared to human participants’ brain activity, as measured by fMRI scans. The AI was then able to predict how the human brain would respond to new sentences based on these patterns. The researchers expanded this by identifying 500 ‘drive’ sentences that would maximally activate the human brain, and ‘suppress’ sentences that would minimize activation. These phrases, when read by a new group of participants, reacted as expected, indicating a successful mapping of the AI’s responses onto human brain activation.
On analysis, the researchers found that more unusual sentences, whether in syntax or meaning, generated stronger neural responses. They also observed that sentences which followed grammar rules but were difficult to understand due to complexity were also strong triggers. Extremely simple sentences or senseless sentences did not evoke much response. Future research intends to investigate if these results are consistent in speakers of languages other than English, and what kind of stimuli activate the right hemisphere of the brain. The study was published in Nature Human Behavior and was supported by various institutions, including the National Institutes of Health and MIT’s Department of Brain and Cognitive Sciences.
