The Growing Evidence
Four major studies from 2025 point to the same conclusion. The populations differ (students, knowledge workers, professionals) and so do the methods (surveys, brain imaging, real-world task analysis), but the finding is consistent: when people delegate their thinking to AI, their cognitive abilities weaken.
The mechanism has a name: cognitive offloading. When you let a tool handle a mental task, your brain stops practising that skill. Over time, the skill deteriorates. The studies below measure exactly how this plays out with AI.
SBS Swiss Business School (Gerlich, 2025)
Published in Societies • DOI: 10.3390/soc15010006
666 participants across three age groups
Strong negative correlation between AI usage and critical thinking scores — statistically significant across all groups
Cognitive offloading was the primary driver, showing an even stronger link to reduced critical thinking ability
Younger users (17-25) showed higher AI dependence and lower critical thinking scores
MIT Media Lab (Kosmyna, 2025)
EEG brain activity study • Covered by TIME Magazine
54 participants writing essays under three conditions: no AI, Google search, ChatGPT
EEG measurement of brain activity across 32 regions
Key Findings
- ChatGPT users showed the lowest brain engagement of any group
- Users demonstrated weaker alpha and theta brain waves, reflecting bypassed memory processes
- 83% of ChatGPT users could not remember passages they had just written
- Users got lazier with each subsequent essay, resorting to copy-paste
- English teachers assessed ChatGPT essays as "soulless" and lacking original thought
- When ChatGPT was removed, users struggled to re-engage the necessary neural networks
Microsoft Research / Carnegie Mellon University (Lee, 2025)
Published at CHI 2025 • Premier human-computer interaction conference
319 knowledge workers, 936 real work task examples
Higher confidence in AI was associated with less critical thinking, while higher self-confidence was associated with more critical thinking
Generative AI changed the nature of critical thinking from original analysis to verification and oversight, a lower-order activity
Harvard Gazette (2025)
Expert perspectives from Harvard faculty
“No learning occurs unless the brain is actively engaged in making meaning.”
— Dan Levy, Harvard Kennedy School
“Critical thinking requires human experience, insight, ethics and moral reasoning. Machines today lack all of that.”
— Fawwaz Habbal, Harvard School of Engineering and Applied Sciences
Jeff Behrends (Harvard Philosophy) noted that taking notes by hand produces greater recall than keystrokes, and that predictive text changes word choices. Delegation of cognitive work has real consequences.
The Pattern
Four studies, different populations, different methods, the same conclusion. When AI does the thinking:
- Critical thinking scores decline significantly
- Brain engagement drops measurably (EEG data)
- Recall deteriorates (83% cannot remember what they wrote)
- Users grow lazier over time (progressive disengagement)
- Thinking shifts from analysis to verification (lower-order activity)
- Removing the AI leaves users unable to re-engage (skill atrophy)
The common thread: when AI does the thinking, the human stops doing it. And cognitive skills, like physical ones, decline when they are not exercised.
The Implication for AI Tools
The research points to a clear design principle: AI tools should keep the human in the thinking loop, not replace it. When the tool does the thinking, the human stops practising the skill. When the tool supports human-led thinking, the skill is exercised and strengthened.
ThinkWrite is built on this principle. Read more about the methodology in Why Thinking Matters in Writing, or explore the full feature set at Why ThinkWrite.
References
- Gerlich, M. (2025). AI Tools in Society: Impacts on Cognitive Offloading and the Future of Critical Thinking. Societies, 15(1), 6. DOI: 10.3390/soc15010006
- Kosmyna, N. (2025). Brain activity study: Writing with no AI, Google search, and ChatGPT. MIT Media Lab. Covered by TIME Magazine.
- Lee, H. et al. (2025). The Impact of Generative AI on Critical Thinking. CHI 2025. Microsoft Research.
- Harvard Gazette (2025). Is AI dulling our minds? Harvard Gazette.