Why Large-Model RL Training Narrows Over Time? ACL 2026 Paper Reveals Entropy Collapse
The article analyzes why reinforcement learning with verifiable rewards (RLVR) for large models experiences rapid policy‑entropy collapse, breaks the phenomenon down to token‑level entropy changes driven by clipping, advantage, token probability and conditional entropy, and introduces STEER, a token‑wise reweighting scheme that stabilizes entropy and yields consistent performance gains on math and code benchmarks.
