Glossary
Cognitive debt
Cognitive debt is the accumulated cost of repeatedly outsourcing mental effort: each delegation saves time immediately and leaves a deficit in learning and critical engagement that compounds across subsequent tasks.
In more detail
The term comes from the MIT Media Lab's 2025 study “Your Brain on ChatGPT”, which asked 54 participants to write essays under three conditions — with an LLM, with a search engine, or unaided — while recording EEG. The LLM group showed the weakest and least distributed neural connectivity of the three, and performed worst at the neural, linguistic and scoring levels across four sessions.
The finding that travels furthest is smaller and stranger than the brain data: when asked to quote from essays they had just submitted, participants in the LLM group frequently could not. They had produced the text without encoding it. The work existed; the learning did not.
The debt metaphor is precise about the mechanism. Like financial debt, the cost is deferred rather than avoided, and it is paid later with interest — in this case as a weaker foundation for the next task, which then makes delegating that task more attractive. The study's own limits are worth stating: 54 participants, 18 in the final crossover session, and only ChatGPT tested.