Your Brain on ChatGPT: Accumulation of Cognitive Debt when Using an AI Assistant for Essay Writing Task
Kosmyna et al., MIT Media Lab · 2025 · arXiv preprint
What it found. Fifty-four participants wrote essays across three conditions — with an LLM, with a search engine, or unaided — under EEG. The LLM group showed the weakest and least distributed neural connectivity of the three, and performed worst at the neural, linguistic and scoring levels across sessions. Asked to quote from essays they had just submitted, LLM-group participants frequently could not.
What it does not show. Fifty-four participants, with only eighteen completing the fourth crossover session. One task type, one model, and a preprint rather than a peer-reviewed publication. It shows reduced engagement during assisted work; it does not show lasting cognitive damage.
Why it is here: The study that introduced 'cognitive debt', and the one most often cited in this conversation.