Ai is literally making people dumber: https://www.microsoft.com/en-us/research/wp-content/uploads/2025/01/lee_2025_ai_critical_thinking_survey.pdf

We surveyed 319 knowledge workers who use GenAI tools (e.g., ChatGPT, Copilot) at work at least once per week, to model how they enact critical thinking when using GenAI tools, and how GenAI affects their perceived effort of thinking critically. Analysing 936 real-world GenAI tool use examples our participants shared, we find that knowledge workers engage in critical thinking primarily to ensure the quality of their work, e.g. by verifying outputs against external sources. Moreover, while GenAI can improve worker efficiency, it can inhibit critical engagement with work and can potentially lead to long-term overreliance on the tool and diminished skill for independent problem-solving. Higher confidence in GenAI’s ability to perform a task is related to less critical thinking effort. When using GenAI tools, the effort invested in critical thinking shifts from information gathering to information verification; from problem-solving to AI response integration; and from task execution to task stewardship. Knowledge workers face new challenges in critical thinking as they incorporate GenAI into their knowledge workflows. To that end, our work suggests that GenAI tools need to be designed to support knowledge workers’ critical thinking by addressing their awareness, motivation, and ability barriers.

I would not say "can potentially lead to long-term overreliance on the tool and diminished skill for independent problem-solving" equals to "literally making people dumber". A sample size of 319 isn't really representative anyways, and they mainly had a sample of a specific type of people. People switch from searching to verifying, which doesn't sound too bad if done correctly. They associate critical thinking with verifying everything ("Higher confidence in GenAI’s ability to perform a task is related to less critical thinking effort"), not sure I agree on this.

This study is also only aimed at people working instead of regular use. I personally discovered so many things with GenAI, and know to always question what the model says when it comes to specific topics or questions, because they tend to hallucinate. You could also say internet made people dumber, but those who know how to use it will be smarter.

https://www.theregister.com/2025/06/18/is_ai_changing_our_brains/

They had to write an essay in 20 minutes... obviously most people would just generate the whole thing and fix little problems here and there, but if you have to think less because you're just fixing stuff instead on inventing.. well yea, you use your brain less. Doesn't make you dumb? It's a bit like saying paying by card makes you dumber because you use less of your brain compared to paying in cash because you have to count how much you need to give, and how much you need to get back.

Yes, if you get helped by a tool or someone, it will be less intensive for your brain. Who would have thought?!