Suxin Ji

Isolating the reinforcement-learning-stage parameter update of a language model, keeping only the single dominant direction of each matrix rescaled to the original magnitude, and injecting it into the language modules of a vision-language model improves matched full-update interpolation in 12 of 15 backbone-benchmark comparisons across three model families and five visual-reasoning benchmarks, including an 8.55 percentage-point MathVision gain on the Qwen recipient. Controls show that matching update magnitude or using arbitrary low-rank directions does not reproduce these gains, indicating that what is acquired during post-training and what remains transferable across models are not the same thing.

Isolating the reinforcement-learning-stage parameter update of a language model, keeping only the single dominant direction of each matrix rescaled to the original magnitude, and injecting it into the language modules of a vision-language model improves matched full-update interpolation in 12 of 15 backbone-benchmark comparisons across three model families and five visual-reasoning benchmarks, including an 8.55 percentage-point MathVision gain on the Qwen recipient. Controls show that matching update magnitude or using arbitrary low-rank directions does not reproduce these gains, indicating that what is acquired during post-training and what remains transferable across models are not the same thing.