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Why can’t I remember what I wrote using ChatGPT?
A pivotal study conducted by researchers at the Massachusetts Institute of Technology (MIT), published in Nature in June 2025, identifies a direct correlation between Large Language Model (LLM) usage and diminished brain activity. The research indicates that utilizing tools like ChatGPT for writing tasks does not simply offload work; it significantly lowers cognitive engagement. The data suggests that the brain becomes less active during AI-assisted tasks, leading to reduced performance that persists even after the user stops using the tool.
Methodology and Metrics
The study measured cognitive load through electroencephalography (EEG) and MRI scans across 54 participants. Researchers divided these individuals into three distinct cohorts for essay writing:
- AI-Assisted Group: Used LLMs like ChatGPT.
- Search Engine Group: Used standard internet search tools.
- Brain-Only Group: Used no digital aids.
The neurological data revealed a steep decline in brain connectivity for the AI-assisted group. While the unassisted group maintained a connectivity score of 79, the AI users dropped to 42 points. This creates a 47% decrease in neural activity. The networks in the brain responsible for critical thinking and memory formation effectively went dormant during the AI-assisted process.
Retention and Authorship Deficits
The behavioral consequences of this reduced activity were immediate. The study found that 83.3% of LLM users could not recall a single sentence of the text they had generated just minutes earlier. In contrast, participants who wrote without AI retained clear memory of their content. Furthermore, the AI group reported the lowest self-perception of authorship, struggling to even cite their own generated work correctly. This indicates a detachment from the creative process that hinders deep learning.
The “Cognitive Hangover” Effect
Perhaps the most critical finding for professionals concerns the lasting impact of LLM usage. In a fourth session where all aids were removed, prior AI users failed to regain normal cognitive function. Their brains continued to show reduced alpha and beta connectivity, and their writing performance remained lower than those who had never used AI. This suggests that heavy reliance on LLMs may cause a form of cognitive impairment that extends beyond the immediate usage session, raising serious questions about the long-term viability of AI-dependent workflows in education and professional development.