David Stromberg of Stockholm University and Victor Lei and Wu Yanhui of the University of Hong Kong set out to fill the gap. They tracked 27,000 pupils aged 12-18 in China, where AI adoption has been fast. Around 80% reported using models such as Doubao and DeepSeek; the other 20% formed the control group.
The drop in exam scores was concentrated among students who rushed their homework. Those who used AI but spent as long on assignments as non-users paid little penalty. What matters, then, is how pupils use the technology