Towards Robust Evaluation of Visual Activity Recognition: Resolving Verb Ambiguity with Sense Clustering

Louie Hong Yao, Nicholas Jarvis, Tianyu Jiang


Abstract
Evaluating visual activity recognition systems is challenging due to inherent ambiguities in verb semantics and image interpretation. When describing actions in images, synonymous verbs can refer to the same event (e.g., *brushing* vs. *grooming*), while different perspectives can lead to equally valid but distinct verb choices (e.g., *piloting* vs. *operating*). Standard exact-match evaluation, which relies on a single gold answer, fails to capture these ambiguities, resulting in an incomplete assessment of model performance. To address this, we propose a vision-language clustering framework that constructs **verb sense clusters**, providing a more robust evaluation. Our analysis of the imSitu dataset shows that each image maps to around four sense clusters, with each cluster representing a distinct perspective of the image. We evaluate multiple activity recognition models and compare our cluster-based evaluation with standard evaluation methods. Additionally, our human alignment analysis suggests that the cluster-based evaluation better aligns with human judgments, offering a more nuanced assessment of model performance.
Anthology ID:
2026.findings-eacl.32
Volume:
Findings of the Association for Computational Linguistics: EACL 2026
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Vera Demberg, Kentaro Inui, Lluís Marquez
Venue:
Findings
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Publisher:
Association for Computational Linguistics
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Pages:
656–672
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URL:
https://preview.aclanthology.org/ingest-eacl/2026.findings-eacl.32/
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Cite (ACL):
Louie Hong Yao, Nicholas Jarvis, and Tianyu Jiang. 2026. Towards Robust Evaluation of Visual Activity Recognition: Resolving Verb Ambiguity with Sense Clustering. In Findings of the Association for Computational Linguistics: EACL 2026, pages 656–672, Rabat, Morocco. Association for Computational Linguistics.
Cite (Informal):
Towards Robust Evaluation of Visual Activity Recognition: Resolving Verb Ambiguity with Sense Clustering (Yao et al., Findings 2026)
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