AI models' written reasoning steps correspond to distinct internal patterns, a new study finds

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Sep 12, 2026

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Can the distinct reasoning steps a language model shows in its text output also be found in its internal states? A new study put it to the test.

When a reasoning model solves a task step by step, it does different things along the way: reading data, breaking down the problem, retrieving a formula, running a calculation. Researchers at South Korea's KAIST and Naver AI Lab wanted to know whether those reasoning steps can also be separated from one another inside the model's numerical representations. They can, and the signal is strongest in the middle layers.