Definition
Plain language
A language model trained to write out its thinking before giving an answer.
As stated in the literature
A class of models post-trained to produce extended chains of thought, often via RL on verifiable rewards, before emitting final answers.
Also called: reasoning models
Why it matters: Allowing extended chains of thought turns out to dramatically improve accuracy on hard problems, at the cost of more tokens and latency per query.
For example, when asked a tricky math problem, the model first writes several paragraphs of step-by-step working before producing its final boxed answer.
Heard on the show
“A research group at ETH Zurich sits down to reproduce a hot new method for training reasoning models.”Episode 009 — How Two Silent Library Bugs Quietly Invalidated a Wave of Reasoning Papers