Wisconsin professor caught 60 AI essays with hidden prompts, now he's dropping writing assignments

A professor at UW–Madison, Timothy Paustian, says he found 60 essays written by AI in a single online microbiology course by using hidden prompts alongside improved detection tools. Paustian told The Atlantic that one tactic was inserting “invisible” instructions inside assignments that only an AI system would follow, including a line telling the model to mention “blueberries.” In his 350-student course, he said the combination helped identify 60 essays the instructor believed were generated with AI. All but one of those students admitted using AI; the only one who didn’t acknowledge it also chose not to appeal a zero grade. The professor is now reconsidering whether writing assignments should remain, noting that detectors are imperfect and may be losing ground as students learn to remove hidden prompts.