PhysVidBench: Language-Grounded Evaluation of Physical Commonsense in Text-to-Video Models

Enes Sanli, Baris Sarper Tezcan, Erkut Erdem, Aykut Erdem


Abstract
Text-to-video (T2V) models now produce striking visuals, yet they routinely violate everyday physics; objects float, tools are misused, and causal sequences break down. Existing benchmarks mostly probe isolated physical laws and rely on vision-language models to score videos directly, which entangles perception and reasoning in one judgment and correlates poorly with humans. We introduce PhysVidBench, a benchmark of 383 base prompts, expanded to 766 prompts with enriched variants and 4,123 manually reviewed QA items, together with a language-grounded evaluation framework that takes a different route: instead of asking a VLM “Is this video physically correct?”, we caption the video, then ask a language model to answer prompt-derived yes/no physics questions using only the captions. This split between seeing and reasoning makes each score traceable to the captions that justify it and aligns more closely with human judgment than direct VLM scoring (Pearson r=0.45–0.69, compared with 0.21–0.47 for the strongest direct VLM evaluator). To test the framework, we carefully curate a set of human-validated prompts spanning seven physical dimensions, with a focus on tool use and affordances – areas largely absent from prior physics-focused benchmarks. Across 12 open and proprietary T2V systems, the best model reaches only 36.2% average accuracy, and no model consistently handles everyday physical reasoning. The same pipeline can also guide iterative error-guided prompt refinement, improving CogVideoX-2B from 21.6 to 32.7 and CogVideoX-5B from 17.8 to 29.7 without retraining.
Anthology ID:
2026.findings-emnlp.2126
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
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
45311–45359
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.2126/
DOI:
10.18653/2026.findings-emnlp.2126
Bibkey:
Cite (ACL):
Enes Sanli, Baris Sarper Tezcan, Erkut Erdem, and Aykut Erdem. 2026. PhysVidBench: Language-Grounded Evaluation of Physical Commonsense in Text-to-Video Models. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 45311–45359, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
PhysVidBench: Language-Grounded Evaluation of Physical Commonsense in Text-to-Video Models (Sanli et al., Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.2126.pdf