Selective Test-Time Debiasing for CLIP via Reward Gating

Jaeho Han, Jisoo Yang, Hyeondong Woo, Mingyu Jeon, Sunjae Yoon, Junyeong Kim


Abstract
Vision language models (VLMs) demonstrate strong zero-shot performance, but often perpetuate social stereotypes in person-centric queries, yielding skewed demographic distributions. Current debiasing methods apply uniform bias corrections across all input queries regardless of their bias sensitivity, creating a fundamental fairness–utility trade-off. Strong debiasing distorts semantically meaningful information in bias-insensitive queries, while weak debiasing fails to mitigate stereotypes in bias-sensitive ones. This one-size-fits-all approach hampers simultaneously achieving high utility on bias-insensitive queries and fairness on bias-sensitive queries. We introduce Reward-Gated Test-Time Adaptation (RG-TTA), a reinforcement learning-based test-time adaptation framework that selectively applies debiasing based on input sensitivity. RG-TTA adaptively triggers fairness regularization based on the bias sensitivity of each input during test-time policy adaptation, while focusing exclusively on optimizing cross-modal alignment for bias-insensitive inputs. Experiments on fairness benchmarks (e.g., FairFace, UTKFace) demonstrate substantial bias reduction while simultaneously improving zero-shot utility, resolving the trade-off of uniform debiasing.
Anthology ID:
2026.acl-long.1320
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
28617–28631
Language:
URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.1320/
DOI:
Bibkey:
Cite (ACL):
Jaeho Han, Jisoo Yang, Hyeondong Woo, Mingyu Jeon, Sunjae Yoon, and Junyeong Kim. 2026. Selective Test-Time Debiasing for CLIP via Reward Gating. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 28617–28631, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Selective Test-Time Debiasing for CLIP via Reward Gating (Han et al., ACL 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.1320.pdf
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 2026.acl-long.1320.checklist.pdf