MemoryRewardBench: Benchmarking Reward Models for Long-Term Memory Management in Large Language Models

Zecheng Tang, Baibei Ji, Ruoxi Sun, Haitian Wang, Juntao Li, Min Zhang


Abstract
With the surge of AI-powered real-world applications, large language models (LLMs) increasingly adopt memory-centric mechanisms to handle multi-turn interactive tasks. Under this paradigm, intermediate processing trajectories, i.e., memory, are central to ensuring LLMs’ faithfulness and effectiveness. Scalable evaluation of the memory management process serves as the cornerstone for further enhancing model performance. Yet, appropriate evaluators for the assessment of memory are currently lacking. Thus, in this work, we seek to employ reward models (RMs) as evaluators and introduce MemoryRewardBench, the first benchmark to systematically study the capability of RMs in assessing LLM memory management processes. MemoryRewardBench covers both long-form comprehension and generation tasks that simulate real-world multi-turn interaction scenarios, featuring 10 distinct settings with different memory management patterns. Evaluations on 13 cutting-edge RMs indicate a diminishing performance gap between open-source and proprietary models, with newer-generation models consistently outperforming their predecessors regardless of parameter count. Additionally, we reveal the fundamental limitations of RMs in evaluating LLMs’ memory.
Anthology ID:
2026.emnlp-main.2574
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
58484–58516
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2574/
DOI:
Bibkey:
Cite (ACL):
Zecheng Tang, Baibei Ji, Ruoxi Sun, Haitian Wang, Juntao Li, and Min Zhang. 2026. MemoryRewardBench: Benchmarking Reward Models for Long-Term Memory Management in Large Language Models. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 58484–58516, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
MemoryRewardBench: Benchmarking Reward Models for Long-Term Memory Management in Large Language Models (Tang et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.2574.pdf