The human brain degenerates after many days of using ChatGPT.

Research indicates that dependence on ChatGPT may cause long-term harm to users' brains.

Báo Khoa học và Đời sống•20/06/2025

The Massachusetts Institute of Technology has just published a study showing that over-reliance on ChatGPT can lead to brain degeneration.

In a laboratory at MIT Media Lab, 54 volunteers aged 18 to 39 are undertaking a seemingly simple task: writing an SAT essay in 20 minutes.

However, what they didn't know was that they were participating in the world's first study using brain-scanning technology to explore the true impact of ChatGPT on the human brain. And the results the scientists obtained sent shivers down their spines.

Dr. Nataliya Kosmyna, the project's lead researcher, monitored the brain activity of volunteers across 32 different regions using EEG devices for four months. She divided them into three groups: the first group used ChatGPT to aid in writing, the second group used Google Search to find information, and the last group relied solely on their own reasoning abilities.

From the very beginning, the differences were evident. The group using ChatGPT showed the lowest level of brain engagement of all three groups and "consistently underperformed at the neurological, linguistic, and behavioral levels." With each essay, they became increasingly lazy, and by the end of the study, many of them had simply copied and pasted content from ChatGPT.

Những khác biệt trong bộ não người sau một thời gian sử dụng các công cụ khác nhau để làm bài tập — Differences in the human brain after using different tools to do exercises for a period of time.

What worried the researchers most wasn't the laziness itself, but what they discovered through brain scans. The essays written by the ChatGPT group were "extremely similar and lacked original thinking," using nearly identical phrasing and ideas. Two English teachers invited to evaluate the essays described them as "soulless" and "empty of content."

But that's just the tip of the iceberg. EEG data shows that those using ChatGPT have low executive control and attention spans. By the third essay, many of them had simply handed the entire job over to ChatGPT. "They just said, 'Give me the essay, refine this sentence, edit it,'" Kosmyna shared.

Conversely, the group that wrote the article without using any assistive tools showed the highest neural connections, particularly in the alpha, theta, and delta brainwave bands—regions associated with creativity, memory, and semantic processing. They were more actively engaged, more curious, and felt more satisfied with their product. The group using Google Search also showed high satisfaction and active brain activity—a notable difference compared to searching for information in AI chatbots.

The reverse experiment further highlighted the harmful effects of AI reliance. When forced to rewrite an old essay without ChatGPT, those who had previously used AI struggled significantly – they could barely remember the essay they had written and exhibited weaker alpha and theta brainwaves. Notably, 83.3% of them were unable to cite sources from essays they had just completed minutes earlier.

Over-reliance on AI tools will cause the human brain to degenerate rapidly.

Brain scan data also revealed a shocking figure: ChatGPT users' neural connections decreased by 47%, from 79 to just 42. As Kosmyna explained: "The task was accomplished, and you could say it was efficient and convenient. But as we showed in the study, you basically didn't integrate anything into your memory network."

Kosmyna decided to publish the study's findings even without peer review because she was concerned that policymakers might implement "GPT for preschoolers" without fully understanding the consequences. "The developing brain is at the highest risk," she warned.

Psychiatrist Zishan Khan, who treats children and adolescents, shared a similar observation: "From a psychiatric perspective, I find that over-reliance on LLMs can have undesirable psychological and cognitive consequences, especially for young people whose brains are still developing."

The study also revealed an interesting paradox: although ChatGPT increased task completion speed by 60%, it reduced "cognitive Germane payload" by 32%—the effort to use memory and intellect to transform information into diagrams—essential for true learning. This is what the researchers call "cognitive debt"—similar to technical debt but for the brain.

What's particularly concerning is that this impact doesn't seem easily reversible. When forced to write without AI assistance, those accustomed to using ChatGPT performed worse than those who had never used AI. This isn't simply dependence, but rather cognitive atrophy—as if your muscles have forgotten how to function.

In just four months of testing, ChatGPT has had a devastating impact on the human brain.

However, the research also offers hope. When the purely writing group was allowed to use ChatGPT, they showed a significant increase in brain connectivity across all EEG frequency bands. This suggests that, if used correctly, AI could enhance learning rather than degrade it.

Kosmyna and her research team are currently conducting a similar study on brain activity in software engineering and programming with and without AI. She revealed that "the results are even worse," which could have significant implications for many companies hoping to replace top-level programmers with AI.

In an interesting detail, Kosmyna intentionally inserted an "AI trap" into the study by predicting that users would use LLM to summarize the paper. As a result, the AI tools were "illusioned" that the study used GPT-4o – information that was completely absent from the original paper.

Kosmyna decided to publish this study even without peer review—something she had never done before. Her motivation stemmed from a fear that in the next six to eight months, some policymakers might decide, "Let's do GPT for preschoolers." "I think that would be absolutely terrible and harmful," she said. "Developing brains like those of young children are at the highest risk."