Preference-Aware Memory Update for Long-Term LLM Agents

Haoran Sun, Zekun Zhang, Shaoning Zeng


Abstract
One of the key factors influencing the reasoning capabilities of LLM-based agents is their ability to leverage long-term memory. Integrating long-term memory mechanisms allows agents to make informed decisions grounded in historical interactions. While recent advances have significantly improved the storage and retrieval components—e.g., by encoding memory into dense vectors for similarity search or organizing memory as structured knowledge graphs—most existing approaches fall short in memory updating. In particular, they lack mechanisms for dynamically refining preference memory representations in response to evolving user behaviors and contexts. To address this gap, we propose a Preference-Aware Memory Update Mechanism (PAMU) that enables dynamic and personalized memory refinement. By integrating sliding window averages (SW) with exponential moving averages (EMA), PAMU constructs a fused preference-aware representation that captures both short-term fluctuations and long-term user tendencies. We conduct experiments on five task scenarios of the LoCoMo dataset, and the results show that our mechanism can significantly improve the output quality of LLM in five baselines, validating its effectiveness in long-term conversations.
Anthology ID:
2026.findings-acl.38
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
783–793
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URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.38/
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Bibkey:
Cite (ACL):
Haoran Sun, Zekun Zhang, and Shaoning Zeng. 2026. Preference-Aware Memory Update for Long-Term LLM Agents. In Findings of the Association for Computational Linguistics: ACL 2026, pages 783–793, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Preference-Aware Memory Update for Long-Term LLM Agents (Sun et al., Findings 2026)
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.38.pdf
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