That is the title of this new paper by a team of researchers affiliated with the MIT Media Lab (Kosmyna, et al., 2025). Although the sample size of their study is small (n = 54), this work is one of the few in the critical thinking literature to conduct an actual experiment: the participants in their study were randomly assigned into one of three groups — the ChatGPT group, the Google Search group, and the “brain-only” group — and the members of each group then had to complete a critical-thinking essay-writing task while they were hooked up to an electroencephalogram (EEG), a machine that measures electrical activity in the brain. Although it looks like the the MIT Media Lab team may have cherry-picked or p-hacked their results (see here), they claim that ChatGPT decimates critical thinking! (Here is a plain-English summary of their findings.) For further reference, below is a compilation of my previous posts on the subject of “Critical thinking in the age of A.I.”:

1. The impact of ChatGPT on critical thinking: prologue (11 June)
2. What is *critical thinking*? A Humean-Bayesian approach (16 June)
3. Critiques of *critical thinking* theory, pedagogy, and practice: an annotated bibliography (17 June)
4. ChatGPT’s pincer attack on critical thinking (18 June)
5. Critical thinking as a communal activity (19 June)
6. John List on critical thinking in the age of A.I. (20 June)