Reinforcement learning made video models second-guess their first answer, and a 'confident first, reflective second' rule recovered 4.1 points
AspireAI community · arXiv
Video models answer from sampled frames and often miss the decisive moment, so the standard remedy is to commit, re-examine the video, then confirm or revise - a loop increasingly learned with reinforcement learning. The authors find RL quietly erodes the first answer: because a wrong initial answer can still be repaired later, a correct one earns less reward, so the initial guess stalls even as the final answer's margin over it grows. Their principle is that the first answer must stay reliable on its own above a floor set by a reference policy, and reflection may only add to it; CoFire implements this by addressing the three erosion channels - reward incentives, parameter drift and gradient interference. It reaches 67.0 percent mean accuracy across Video-MME, MLVU and LongVideoBench, 1.7 points above the strongest compared 7B method, and beats outcome-reward RL by 4.1 points on initial-answer accuracy and 3.7 on final accuracy.
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