Understanding the Effects of Distractors on Reasoning Vision-Language Models

Jiyun Bae, Hyunjong Ok, Sangwoo Mo, Jaeho Lee


Abstract
How does irrelevant information (i.e., distractors) affect test-time scaling in vision-language models (VLMs)? Prior work on text-only language models has shown that textual distractors can intensify inverse scaling, causing models to reason longer but less effective reasoning traces. In this work, we investigate whether similar phenomena arise in multimodal settings. We introduce Idis (Images with distractors), a visual question-answering dataset that systematically varies distractors along semantic and numerical dimensions. Our analyses reveal that visual distractors affect reasoning VLMs in a fundamentally different way from textual distractors: although inverse scaling still emerges, visual distractors reduce accuracy without increasing reasoning length. We further show that attribute counts extracted from reasoning traces provide key insights into how distractors interact with reasoning length and accuracy. As a sanity check, we propose a simple prompting strategy that mitigates distractor-driven predictions in reasoning vision-language models.
Anthology ID:
2026.emnlp-main.1114
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
25513–25542
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1114/
DOI:
Bibkey:
Cite (ACL):
Jiyun Bae, Hyunjong Ok, Sangwoo Mo, and Jaeho Lee. 2026. Understanding the Effects of Distractors on Reasoning Vision-Language Models. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 25513–25542, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Understanding the Effects of Distractors on Reasoning Vision-Language Models (Bae et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1114.pdf