A study by David Stromberg of Stockholm University, Victor Lei, and Wu Yanhui of the University of Hong Kong tracked 27,000 Chinese students aged 12 to 18 and found a gap between AI-assisted homework performance and unaided exam results. About 80% of surveyed students reported using AI models including Doubao and DeepSeek, while the 20% who did not use AI served as a control group. Over six months, students using AI increased their average homework scores by 18% across subjects, according to figures reported by The Economist on August 18. Under exam conditions without AI access, those students scored 20% below classmates who had not used the tools during the period. The researchers’ full study had not been independently verified by other institutions at the time of publication. A 2024 University of Pennsylvania study found a similar pattern in math: students using ChatGPT or an AI tutoring program did better during practice but did not retain that advantage on a later closed-book test. A Brookings Institution tip sheet cautioned that AI can support learning when used intentionally, while overreliance that substitutes for thinking, social interaction, or creativity may hinder cognitive and social-skill development.