Harvard astronomer Avi Loeb is perhaps best known for raising eyebrows with public suggestions that various stellar phenomena could be evidence of extraterrestrial civilization. It’s controversial, to be sure — but if nothing else, at least Loeb’s using his own brain, at a time when dependence on AI chatbots has never been higher.
In a recent essay on his personal blog, the Harvard professor lamented the mental decay among the AI users in his life.
“Recently, I noticed that some people around me are starting to lose their cognitive abilities as a result of excessive use of Artificial Intelligence (AI) platforms, such as ChatGPT, Claude or Gemini,” Loeb wrote. “This phenomenon resembles muscle loss from excessive use of public transportation as a substitute for walking. In academia, the only reliable way of testing the cognitive abilities of students right now is by placing them in a Faraday cage.”
Nevermind studies showing that public transit users walk a tremendous amount — a much better analogue would be drivers, really — Loeb is underscoring a real and growing concern by many researchers and educators.
Since the rise of AI chatbots over the past few years, there have been plenty of research papers, anecdotal evidence, and grim predictions outlining this exact phenomenon. As one 2025 study by Swiss researcher Michael Gerlich found, frequent use of AI tools can cause critical thinking abilities to atrophy, resulting in a “cognitive cost” among human users.
As the number of AI users ticks up, the long-term risks of systemic intellectual debt only become more apparent. As recent research by the Pew Research Center found, a massive number of school-aged teens are using AI to do their homework, with heavy use concentrated among minority and low-income students.
As far as Loeb is concerned, he writes that the threat of this kind of societal cognitive impairment makes it important to push back against the idea of AI systems as a sort of magical stand-in for the human brain.
“Regarding AI as similar to the beauty of the human mind is just like putting lipstick on a pig,” he pontificates. “I am much more excited about the potential to discover truly alien intelligence from another star.”