Quantifying and Mitigating Default Behaviors in Text-to-Image Models

Royi Rassin, Aviv Slobodkin, Shauli Ravfogel, Yanai Elazar, Yoav Goldberg


Abstract
Text-to-image (T2I) models consistently collapse to stereotypical attribute values when prompts leave concepts underspecified, a phenomenon we term default behaviors. We conduct a large-scale empirical study using , an LLM-driven measurement approach that quantifies diversity at the level of individual concept attributes. We find pervasive default behaviors across all evaluated T2I models, with stronger models tending to exhibit less diversity. We trace these defaults to reporting bias in training captions: when captions omit common attributes, the accompanying images are dominated by a narrow set of values, and model outputs closely mirror this skew. We confirm this link causally with controlled fine-tuning interventions. As a proof of concept, we show that making sampled attribute values explicit broadens outputs, with some loss of faithfulness to secondary prompt details. Together, our results recast low diversity not as an inherent limitation of T2I models, but as a measurable and steerable consequence of what their training captions leave unsaid. Code and data available at: https://royira.github.io/GRADE.
Anthology ID:
2026.findings-emnlp.1596
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
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SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
33994–34024
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1596/
DOI:
Bibkey:
Cite (ACL):
Royi Rassin, Aviv Slobodkin, Shauli Ravfogel, Yanai Elazar, and Yoav Goldberg. 2026. Quantifying and Mitigating Default Behaviors in Text-to-Image Models. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 33994–34024, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Quantifying and Mitigating Default Behaviors in Text-to-Image Models (Rassin et al., Findings 2026)
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https://aclanthology.org/2026.findings-emnlp.1596.pdf