In 2025, after the advent of Large Language Models (LLMs) like ChatGPT, writing an essay has never been easier. Need research? A structure? Maybe an abstract here, or a conclusion there? Other than the obvious environmental costs behind using these services, what is the human cost in using LLMs in your education? A new study suggests using ChatGPT to help you complete essays has an impact on your brain.
The study by Dr. Kosmyna, a research scientist at MIT Media Lab, looked at the neural and behavioural consequences of using LLMs for essay writing. Participants were split into three groups: LLM, search engine, and Brain-only. Each group completed three tasks under the same condition, but for the fourth task, LLM users and the Brain-only group swapped conditions.
Measuring results through an ECG found that participants writing essays using LLMs has the least brain connectivity, as opposed to those in the search engine or brain-only groups. Furthermore, the brain-only group showed the strongest neural activity, which indicates a deeper cognitive effort. Interestingly, there is evidence these tools dull our essay-writing skills over time as participants who switched from LLM use to brain-only essay writing showed reduced neural engagement, this could suggest a possible cognitive ‘deconditioning’.
Aside from the effects LLMs have on our brains, the two other main takeaways from the study are the group relying on writing essays with LLMs had the lowest sense of authorship of their essays and had difficulty remembering their work, and the essay quality actually declined. The LLM group’s essays were more similar in structure, and overall were graded lower by the human and AI evaluators used in the study.
The above results from the study show the long-term educational risks of using and relying on LLMs. While they might be tempting for a quick fix when you’re tight on a deadline, the negative impact they have on your memory, writing, and critical thinking skills highlights why they should not be used in the education sector.