Don’t Just Look, Intervene: Perturbation Based Region Labeling for VQA Images

Marko Jojic, Zhaonan Li, Ben Zhou


Abstract
Vision Language Models (VLMs) should rely on visual evidence that directly determines the correct answer, but supervision for grounding visual reasoning is often expensive to obtain manually or tied to dataset-specific annotation primitives. We instead introduce model-causal visual evidence as an annotation target, defined as the set of image regions whose counterfactual intervention changes a model’s answer distribution for a given image-question pair. Based on this principle, we introduce Counterfactual Search for Grounding Regions (CSGR). CSGR is a scalable pipeline that proposes candidate regions, perturbs them, measures their effect on answer sensitivity, and aggregates this evidence across multiple judges to approximate answer-critical regions in VQA data. To assess whether CSGR annotations contain a useful supervision signal, we plug them into three existing grounding-aware training routines: attention steering, Visual CoT finetuning, and latent visual reasoning. These experiments test whether the proposed annotation scheme can provide a useful supervision signal across multiple ways of consuming region labels, rather than introducing a new way of using them. Across competing automatic region-labeling mechanisms, CSGR annotations provide the most consistent gains over Cross Entropy-only finetuning in both in-domain and out-of-domain evaluations, indicating that the proposed labeling scheme captures useful region-level information.
Anthology ID:
2026.findings-emnlp.468
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:
9822–9835
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.468/
DOI:
Bibkey:
Cite (ACL):
Marko Jojic, Zhaonan Li, and Ben Zhou. 2026. Don’t Just Look, Intervene: Perturbation Based Region Labeling for VQA Images. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 9822–9835, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Don’t Just Look, Intervene: Perturbation Based Region Labeling for VQA Images (Jojic et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.468.pdf