Macro: Enhancing Multilingual Counterfactual Explanations through Alignment-as-Preference Optimization

Yilong Wang, Qianli Wang, Bohao Chu, Yihong Liu, Jing Yang, Simon Ostermann


Abstract
Self-generated counterfactual explanations (SCEs) are minimally modified inputs minimality generated by large language models (LLMs) that flip their own predictions validity, offering a causally grounded approach to unraveling black-box LLM behavior. Yet extending them beyond English remains challenging: existing methods struggle to produce valid SCEs in non-dominant languages, and a persistent trade-off between validity and minimality undermines explanation quality. We introduce Macro, a preference alignment framework that applies Direct Preference Optimization (DPO) to multilingual SCE generation, using a composite scoring function to construct preference pairs that effectively translate the trade-off into measurable preference signals. Experiments across four LLMs and seven typologically diverse languages show that Macro improves validity by 12.55% on average over the chain-of-thought baseline without degrading minimality, while avoiding the severe minimality violations of the translation-based baseline. Compared to supervised fine-tuning, Macro achieves superior performance on both metrics, confirming that explicit preference optimization is essential for balancing this trade-off. Further analyses reveal that Macro increases cross-lingual perturbation alignment and mitigates common generation errors. Our results highlight preference optimization as a promising direction for enhancing multilingual model explanations.
Anthology ID:
2026.findings-emnlp.151
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:
3176–3210
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.151/
DOI:
Bibkey:
Cite (ACL):
Yilong Wang, Qianli Wang, Bohao Chu, Yihong Liu, Jing Yang, and Simon Ostermann. 2026. Macro: Enhancing Multilingual Counterfactual Explanations through Alignment-as-Preference Optimization. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 3176–3210, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Macro: Enhancing Multilingual Counterfactual Explanations through Alignment-as-Preference Optimization (Wang et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.151.pdf