Unilogit: Robust Machine Unlearning for LLMs Using Uniform-Target Self-Distillation

Stefan Vasilev, Christian Herold, Baohao Liao, Seyyed Hadi Hashemi, Shahram Khadivi, Christof Monz


Abstract
This paper introduces Unilogit, a novel self-distillation method for machine unlearning in Large Language Models. Unilogit addresses the challenge of selectively forgetting specific information while maintaining overall model utility, a critical task in compliance with data privacy regulations like GDPR. Unlike prior methods that rely on static hyperparameters or starting model outputs, Unilogit dynamically adjusts target logits to achieve a uniform probability for the target token, leveraging the current model’s outputs for more accurate self-distillation targets. This approach not only eliminates the need for additional hyperparameters but also enhances the model’s ability to approximate the golden targets. Extensive experiments on public benchmarks and an in-house e-commerce dataset demonstrate Unilogit’s superior performance in balancing forget and retain objectives, outperforming state-of-the-art methods such as NPO and UnDIAL. Our analysis further reveals Unilogit’s robustness across various scenarios, highlighting its practical applicability and effectiveness in achieving efficacious machine unlearning.
Anthology ID:
2025.findings-acl.1154
Volume:
Findings of the Association for Computational Linguistics: ACL 2025
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
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Pages:
22453–22472
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URL:
https://preview.aclanthology.org/landing_page/2025.findings-acl.1154/
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Cite (ACL):
Stefan Vasilev, Christian Herold, Baohao Liao, Seyyed Hadi Hashemi, Shahram Khadivi, and Christof Monz. 2025. Unilogit: Robust Machine Unlearning for LLMs Using Uniform-Target Self-Distillation. In Findings of the Association for Computational Linguistics: ACL 2025, pages 22453–22472, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
Unilogit: Robust Machine Unlearning for LLMs Using Uniform-Target Self-Distillation (Vasilev et al., Findings 2025)
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https://preview.aclanthology.org/landing_page/2025.findings-acl.1154.pdf