Do Vision-Language-Action Models Mean What They Say? On the Role of Faithfulness in Embodied Reasoning
Embodied Chain-of-Thought has emerged as a promising mechanism to enhance robot decision-making and interpretability in black-box Vision-Language Action (VLA) models. However, whether this verbalized Chain-of-Thought truthfully reflects the policy's underlying decision process remains poorly understood. We distinguish between functional reasoning, in which reasoning improves task performance, and faithful reasoning, in which reasoning truly reflects the policy's internal decision process. We argue that SoTA alignment strategies offer a necessary but insufficient notion of faithfulness, admitting reasoning whose intermediate steps can mask the causal links in action prediction through conf...
| Authors | Matthew Foutter, Matteo Cercola, Lena Wild et al. |
|---|---|
| Primary category | cs.RO |
| Published | 6 July 2026 |
| Last updated at source | 6 July 2026 |
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