MIT researchers conducted a study examining the cognitive impact of using ChatGPT versus Google Search or no tools during essay writing tasks. The study involved 54 participants divided into three groups: one using ChatGPT (LLM group), one using Google Search, and one relying solely on their own cognitive abilities (Brain-only group). Over multiple sessions, participants wrote essays while their brain activity was monitored using electroencephalography (EEG).
ChatGPT users exhibited the lowest brain engagement, showing significantly weaker neural connectivity, especially in alpha and beta EEG bands associated with executive function, creativity, and memory processing. This group demonstrated under-engagement compared to the Search Engine group (moderate engagement) and the Brain-only group (strongest engagement).
The ChatGPT group also showed reduced memory retention and difficulty recalling or quoting their own essay content, reflecting a phenomenon termed “cognitive offloading,” where reliance on AI reduces mental effort and ownership of work. Participants who switched from ChatGPT to writing without tools struggled to re-engage brain regions effectively, indicating potential long-term cognitive costs of early AI reliance. Conversely, those transitioning from no tools to AI assistance showed increased neural activity due to adapting to the new tool.
Essays produced with ChatGPT were found to be more homogeneous and less original, with lower perceived ownership and creativity, as assessed by human teachers and AI judges.
Overall, the study highlights that while ChatGPT offers convenience, its use in writing tasks may diminish cognitive engagement, creativity, and memory, raising concerns about its long-term educational implications and the need for careful integration of AI tools in learning environments.