Learning When to Think in Latent Visual Space: Reasoning Mode Adaptive Reinforcement Learning

Paul Jian, Jinpeng Ou, Leo Wei, Qingpei Guo, Jianing Li


Abstract
Latent Visual Reasoning (LVR) unfolds reasoning in a continuous visual embedding space, markedly improving Vision-Language Models (VLMs) on vision-intensive tasks. However, our experiments reveal a hidden cost: LVR inevitably undermines VLMs’ strong textual reasoning ability, causing substantial degradation on logic-intensive tasks. This motivates us to unify both reasoning modes within a single VLM that adaptively selects the appropriate one. We propose MoLaT (Mixture of Latent and Textual Reasoning), a novel method that trains VLMs via reinforcement learning (RL) to select LVR and text-only reasoning adaptively. MoLaT is trained in two stages. Supervised fine-tuning endows the VLM with a dual-mode capability using mixed CoT data. Then, MoLaT introduces two complementary designs: 1) The mode-adaptive advantage decouples the mode-selection signal from per-rollout correctness reward at the token level: mode-selection tokens receive dedicated cross-mode gradients, while content tokens retain the group-relative advantage. 2) The entropy-modulated advantage weight uses sequence-level entropy as a difficulty proxy, modulating signal strength to prevent premature mode commitment. Experiments confirm that MoLaT improves both vision-intensive and logic-intensive abilities, validating adaptive mode selection as key to general-purpose reasoning VLMs.
Anthology ID:
2026.findings-emnlp.1986
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
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SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
42327–42349
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URL:
https://aclanthology.org/2026.findings-emnlp.1986/
DOI:
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Cite (ACL):
Paul Jian, Jinpeng Ou, Leo Wei, Qingpei Guo, and Jianing Li. 2026. Learning When to Think in Latent Visual Space: Reasoning Mode Adaptive Reinforcement Learning. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 42327–42349, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Learning When to Think in Latent Visual Space: Reasoning Mode Adaptive Reinforcement Learning (Jian et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1986.pdf