A 26,000-student study shows AI's hidden learning cost takes two full years to surface

26000名学生研究显示AI隐藏学习成本需两年才显现

A 30-month panel study of 26,000 secondary students in central China found that AI use raised homework scores by 18% and cut completion time from 64 to 45 minutes, but closed-book exam scores dropped 20%. The full 18–24% decline on high-stakes entrance exams took about two years to appear. Roughly 81% of long-term users showed an outsourcing pattern—fast homework, high grades, poor exams. Students who spent similar time as non-users saw no exam penalty. Social sciences took the biggest hit at 27%. The post does not name the county or the lead institution.

Why it matters: Large-scale longitudinal study with solid data (26k students, 2.5 years) revealing a hidden cost of AI-assisted learning that takes two years to surface. HKR all hit, but single-county scope and paywalled source keep it from scoring higher pending more detail.