AI help raised short-term scores, then weakened independent performance
The unnerving part of this study is not that AI gave wrong answers. It often helped people solve the immediate problem. The cost appeared after the tool was removed. In randomized experiments involving 1,222 participants, researchers tested fraction problems and reading comprehension. Across the experiments, assisted performance improved, but later unaided performance fell. Participants also skipped more problems in some conditions. The pattern appeared after roughly ten to fifteen minutes of use. That is an experimental result about short tasks, not evidence that any individual's intelligence has permanently declined. One replication found a smaller accuracy gap, and its overall skip-rate difference was not statistically significant. A subgroup analysis suggested the largest persistence cost among people who sought direct answers, but that comparison was observational within the trial and should not be called causal. The practical implication is a design choice: an assistant that always finishes the problem may optimize the visible score while removing the practice that builds competence. Teachers and employers should test what people can do without the tool, not merely count AI-assisted output. Developers could compare answer-giving against hint-first or delayed-help designs. The paper began as an April preprint and was revised October 3; it is not a new experiment performed today.
