A field experiment with nearly 1,000 high school math students in Turkey offers one of the clearest pictures yet of how AI can help in the moment and hurt later.

Researchers Hamsa Bastani, Osbert Bastani, Alp Sungu, Haosen Ge, Özge Kabakcı and Rei Mariman compared three groups: students with a standard ChatGPT-style assistant ("GPT Base"), students with a tutor version that gave hints and included teacher input ("GPT Tutor"), and a control group with only textbooks and notes. The study was published in the Proceedings of the National Academy of Sciences in 2025.

The results

Group

Practice vs. control

Exam without AI vs. control

GPT Base

48% better

17% worse

GPT Tutor

127% better

No difference

The chat logs explain the gap. Most students using GPT Base simply asked for the answer and copied it, sometimes including its mistakes.

"If humans don't learn, if they start using these tools as a crutch and rely on it, they won't actually build those fundamental skills," Hamsa Bastani told Knowledge at Wharton.

What it means for buyers

The difference between harm and help came from product design, not from whether AI was present. When evaluating AI tutors, schools should ask vendors:

  • Does the tool give answers by default, or hints?
  • Can teachers shape what it will and won't do?
  • Is there evidence of learning without the tool, not just better performance with it?

Sources