Beyond Markovian Forgetfulness: Episodic Memory for Reasoning-Intensive Retrieval

Dohyeon Lee, Yeonseok Jeong, Seung-won Hwang


Abstract
Reasoning-intensive information retrieval uses large language models to solve complex queries via multi-step reasoning. However, existing methods have critical limitations. Chain-of-Thought (CoT) approaches suffer from inefficiency, while state-based methods, despite better token efficiency, often fall into reasoning cycles that trap the query refinement process. To address these issues, we propose Episodic Memory for Retrieval (EMR), which enhances the state-based framework with an episodic memory. This module stores the full history of prior states for a query, allowing the model to avoid repetition of such cycles. Experiments on the BRIGHT benchmark show that EMR consistently outperforms both CoT and state-based baselines. Moreover, it is highly token-efficient, reducing token usage by 72% on average. Our results show that episodic memory is an effective and token-efficient mechanism for reasoning-intensive retrieval. The gains also generalize across different base models and stay efficient in terms of end-to-end latency. The code is available in https://github.com/ldilab/EMR.
Anthology ID:
2026.acl-long.1728
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
ACL
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Publisher:
Association for Computational Linguistics
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Pages:
37266–37280
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URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.1728/
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Cite (ACL):
Dohyeon Lee, Yeonseok Jeong, and Seung-won Hwang. 2026. Beyond Markovian Forgetfulness: Episodic Memory for Reasoning-Intensive Retrieval. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 37266–37280, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Beyond Markovian Forgetfulness: Episodic Memory for Reasoning-Intensive Retrieval (Lee et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-long.1728.pdf
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