Machine Heart

Jul 15, 2026 · Artificial Intelligence

Why Does Large‑Model RL Training Narrow? Entropy Insights from ACL Paper

Large‑model reinforcement learning with verifiable rewards often suffers entropy collapse, causing exploration to shrink; this article dissects the phenomenon at the token level, identifies four influencing factors, critiques existing entropy interventions, and introduces STEER—a token‑wise reweighting scheme that stabilizes entropy dynamics and yields consistent gains on math reasoning and coding benchmarks.