Using ChatGPT too much? Beware! MIT study shows AI-assisted work weakens critical thinking and memory

At MIT’s Media Lab, a team of neurologists and AI experts has delivered a jolt to the ongoing debate over AI’s place in education and work. In a study that wired volunteers to EEG monitors as they wrote essays, the researchers found that using large language models (LLMs) like ChatGPT may do more than just help or hinder productivity — it might actually dull the brain’s cognitive muscle over time.

With LLMs like ChatGPT becoming a go-to tool for tasks ranging from school essays to corporate briefs, MIT researchers wanted to know: what are these tools doing to our brains?

They enlisted 54 volunteers and split them into three groups. Each was tasked with writing a 20-minute essay on philanthropy across three separate sessions. One group used ChatGPT, another used Google Search, and a third — the “Brain-only” group — had to rely solely on their own thinking.

All participants wore EEG monitors to track brain activity, including cognitive effort and mental workload. Their essays were also evaluated using natural language processing tools and scored by both human teachers and an AI model. Post-task interviews rounded out the data collection.

The differences were striking. The Brain-only group consistently showed the highest levels of brain connectivity and activity. Google users came next. The ChatGPT group registered the lowest brain engagement across the board.

Months later, 18 participants returned for a fourth session with the groups switched: ChatGPT users went Brain-only, and vice versa. The prior ChatGPT users continued to show weak neural connectivity, while those who had previously worked unaided retained stronger memory and showed greater brain activity.

In post-session interviews, those who used ChatGPT described feeling less ownership over their essays and had trouble recalling or quoting their own writing — even shortly after finishing.

Overall, the findings are clear: relying on LLMs like ChatGPT may weaken critical thinking and memory recall. While helpful in the short term, frequent use could erode cognitive skills that are vital for deep learning and meaningful engagement with content.