What Users Leave Unsaid: Under-Specified Queries Limit Vision-Language Models

Dasol Choi, Guijin Son, Hanwool Lee, Minhyuk Kim, Hyunwoo Ko, Teabin Lim, Eungyeol Ahn, Jungwhan Kim, Seunghyeok Hong, Youngsook Song


Abstract
Current vision-language benchmarks predominantly feature well-structured questions with clear, explicit prompts. However, real user queries are often informal and underspecified. Users naturally leave much unsaid, relying on images to convey context. We introduce HAERAE-Vision, a benchmark of 653 real-world visual questions from Korean online communities (0.76% survival from 86K candidates), each paired with an explicit rewrite, yielding 1,306 query variants in total. Evaluating 39 VLMs, we find that even state-of-the-art models (GPT-5, Gemini 2.5 Pro) achieve under 50% on the original queries. Crucially, query explicitation alone yields 8 to 22 point improvements, with smaller models benefiting most. We further show that even with web search, under-specified queries underperform explicit queries without search, revealing that current retrieval cannot compensate for what users leave unsaid. Our findings demonstrate that a substantial portion of VLM difficulty stem from natural query under-specification instead of model capability, highlighting a critical gap between benchmark evaluation and real-world deployment.
Anthology ID:
2026.findings-acl.528
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
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San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
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Findings
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Publisher:
Association for Computational Linguistics
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Pages:
10863–10886
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.528/
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Cite (ACL):
Dasol Choi, Guijin Son, Hanwool Lee, Minhyuk Kim, Hyunwoo Ko, Teabin Lim, Eungyeol Ahn, Jungwhan Kim, Seunghyeok Hong, and Youngsook Song. 2026. What Users Leave Unsaid: Under-Specified Queries Limit Vision-Language Models. In Findings of the Association for Computational Linguistics: ACL 2026, pages 10863–10886, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
What Users Leave Unsaid: Under-Specified Queries Limit Vision-Language Models (Choi et al., Findings 2026)
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.528.pdf
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