UTILMEM: Benchmarking Evidence Utilization in Long-Term Conversational Memory

Peijun Qing, Fobo Shi, Soroush Vosoughi


Abstract
Long-term memory is increasingly important for conversational agents, yet existing benchmarks primarily measure memory through pointwise factual recall: whether a system can recover isolated facts or event-level details from prior interactions. Real-world memory use, however, often requires a more demanding capability: integrating distributed, implicit, and noisy evidence across extended interaction histories into coherent, task-oriented outputs. We call this capability memory utilization. Here, we introduce UtilMem, a diagnostic benchmark comprising 1,717 instances across five domains, designed to evaluate four underexplored aspects of memory utilization: reasoning over dense histories, identifying implicitly relevant memories, synthesizing distributed evidence into summaries, analyses, or plans, and resisting interference from semantically similar distractors. Evaluating a diverse set of retrieval-based and memory-augmented systems, we find that strong performance on conventional factual-memory benchmarks does not reliably translate into effective memory utilization. Moreover, retrieval alone is insufficient: even when relevant evidence is successfully recovered, systems frequently fail to integrate information across sessions or to distinguish useful evidence from plausible distractors. These findings expose a substantial gap between accessing stored information and using it effectively, and suggest that progress in long-term conversational memory will require architectures that explicitly support evidence integration and robustness to retrieval interference. Code is available at https://github.com/peijunallin/UtilMem.
Anthology ID:
2026.emnlp-main.1639
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:
37249–37272
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1639/
DOI:
Bibkey:
Cite (ACL):
Peijun Qing, Fobo Shi, and Soroush Vosoughi. 2026. UTILMEM: Benchmarking Evidence Utilization in Long-Term Conversational Memory. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 37249–37272, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
UTILMEM: Benchmarking Evidence Utilization in Long-Term Conversational Memory (Qing et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1639.pdf