Visual Planning: Let's Think Only with Images
Authors: name: Yi Xu, name: Chengzu Li, name: Han Zhou, name: Xingchen Wan, name: Caiqi Zhang, name: Anna Korhonen, name: Ivan Vulić

Recent advancements in Large Language Models (LLMs) and their multimodal
extensions (MLLMs) have substantially enhanced machine reasoning across diverse
tasks. However, these models predominantly rely on pure text as the medium for
both expressing and structuring reasoning, even when visual information is
present. In this work, we argue that language may not always be the most
natural or effective modality for reasoning, particularly in tasks involving
spatial and geometrical information. Motivated by this, we propose a new
paradigm, Visual Planning, which enables planning through purely visual
representations, independent of text. In this paradigm, planning is executed
via sequences of images that encode step-by-step inference in the visual
domain, akin to how humans sketch or visualize future actions. We introduce a
novel reinforcement learning framework, Visual Planning via Reinforcement
Learning (VPRL), empowered by GRPO for post-training large vision models,
leading to substantial improvements in planning in a selection of
representative visual navigation tasks, FrozenLake, Maze, and MiniBehavior. Our
visual planning paradigm outperforms all other planning variants that conduct
reasoning in the text-only space. Our results establish Visual Planning as a
viable and promising alternative to language-based reasoning, opening new
avenues for tasks that benefit from intuitive, image-based inference.