Beyond Isolated Behaviors: Hierarchical User Modeling for LLM Personalization

Liang Wang, Xinyi Mou, Xiaoyou Liu, Tiannan Wang, Yuqing Wang, Zhongyu Wei


Abstract
Large Language Models (LLMs) have demonstrated remarkable capabilities across diverse domains, yet personalizing their outputs to individual users remains an open challenge. Existing approaches predominantly adopt a flat behavioral paradigm, aggregating user behaviors without an explicit account of how they are organized into deeper behavioral structures. In this work, we draw on Pierre Bourdieu’s Theory of Practice to propose PHF (Practice-Habitus-Field), a sociologically grounded framework that reconceptualizes LLM personalization through three hierarchical levels: individual behaviors as practices, their temporal accumulation into stable dispositions as habitus, and shared regularities across similar users as fields. We instantiate PHF through PHF Compass, a lightweight and model-agnostic implementation based on a frozen LLM. Experiments on the Language Model Personalization (LaMP) benchmark demonstrate consistent improvements across diverse tasks, while further analyses validate the interpretability and extensibility of the learned behavioral structures.
Anthology ID:
2026.findings-emnlp.259
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
Note:
Pages:
5432–5448
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.259/
DOI:
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Cite (ACL):
Liang Wang, Xinyi Mou, Xiaoyou Liu, Tiannan Wang, Yuqing Wang, and Zhongyu Wei. 2026. Beyond Isolated Behaviors: Hierarchical User Modeling for LLM Personalization. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 5432–5448, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Beyond Isolated Behaviors: Hierarchical User Modeling for LLM Personalization (Wang et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.259.pdf