Why Steering Works: Toward a Unified View of Language Model Parameter Dynamics

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Hauptverfasser: Xu, Ziwen, Wu, Chenyan, Sun, Hengyu, Hong, Haiwen, Wang, Mengru, Yao, Yunzhi, Huang, Longtao, Xue, Hui, Deng, Shumin, Chu, Zhixuan, Chen, Huajun, Zhang, Ningyu
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Veröffentlicht: 2026
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author Xu, Ziwen
Wu, Chenyan
Sun, Hengyu
Hong, Haiwen
Wang, Mengru
Yao, Yunzhi
Huang, Longtao
Xue, Hui
Deng, Shumin
Chu, Zhixuan
Chen, Huajun
Zhang, Ningyu
author_facet Xu, Ziwen
Wu, Chenyan
Sun, Hengyu
Hong, Haiwen
Wang, Mengru
Yao, Yunzhi
Huang, Longtao
Xue, Hui
Deng, Shumin
Chu, Zhixuan
Chen, Huajun
Zhang, Ningyu
contents Methods for controlling large language models (LLMs), including local weight fine-tuning, LoRA-based adaptation, and activation-based interventions, are often studied in isolation, obscuring their connections and making comparison difficult. In this work, we present a unified view that frames these interventions as dynamic weight updates induced by a control signal, placing them within a single conceptual framework. Building on this view, we propose a unified preference-utility analysis that separates control effects into preference, defined as the tendency toward a target concept, and utility, defined as coherent and task-valid generation, and measures both on a shared log-odds scale using polarity-paired contrastive examples. Across methods, we observe a consistent trade-off between preference and utility: stronger control increases preference while predictably reducing utility. We further explain this behavior through an activation manifold perspective, in which control shifts representations along target-concept directions to enhance preference, while utility declines primarily when interventions push representations off the model's valid-generation manifold. Finally, we introduce a new steering approach SPLIT guided by this analysis that improves preference while better preserving utility. Code is available at https://github.com/zjunlp/EasyEdit/blob/main/examples/SPLIT.md.
format Preprint
id arxiv_https___arxiv_org_abs_2602_02343
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Why Steering Works: Toward a Unified View of Language Model Parameter Dynamics
Xu, Ziwen
Wu, Chenyan
Sun, Hengyu
Hong, Haiwen
Wang, Mengru
Yao, Yunzhi
Huang, Longtao
Xue, Hui
Deng, Shumin
Chu, Zhixuan
Chen, Huajun
Zhang, Ningyu
Computation and Language
Artificial Intelligence
Computer Vision and Pattern Recognition
Information Retrieval
Machine Learning
Methods for controlling large language models (LLMs), including local weight fine-tuning, LoRA-based adaptation, and activation-based interventions, are often studied in isolation, obscuring their connections and making comparison difficult. In this work, we present a unified view that frames these interventions as dynamic weight updates induced by a control signal, placing them within a single conceptual framework. Building on this view, we propose a unified preference-utility analysis that separates control effects into preference, defined as the tendency toward a target concept, and utility, defined as coherent and task-valid generation, and measures both on a shared log-odds scale using polarity-paired contrastive examples. Across methods, we observe a consistent trade-off between preference and utility: stronger control increases preference while predictably reducing utility. We further explain this behavior through an activation manifold perspective, in which control shifts representations along target-concept directions to enhance preference, while utility declines primarily when interventions push representations off the model's valid-generation manifold. Finally, we introduce a new steering approach SPLIT guided by this analysis that improves preference while better preserving utility. Code is available at https://github.com/zjunlp/EasyEdit/blob/main/examples/SPLIT.md.
title Why Steering Works: Toward a Unified View of Language Model Parameter Dynamics
topic Computation and Language
Artificial Intelligence
Computer Vision and Pattern Recognition
Information Retrieval
Machine Learning
url https://arxiv.org/abs/2602.02343