Accurate but Not Humble: Evaluating Epistemic Humility in LLM Agents under Knowledge Conflict

Kaiser Sun, Bernal Jiménez Gutiérrez, Hongjun Liu, Jingyu Zhang, Jie Gao, Mark Dredze, Daniel Khashabi


Abstract
When retrieved evidence contradicts an agent’s prior beliefs, does it revise its answer, acknowledge uncertainty, or persist with an incorrect conclusion? Existing evaluations of agentic systems focus primarily on task success, offering limited insight into how agents handle such conflicts. We propose to evaluate agents on epistemic humility (EH): the agent’s willingness to recognize, act on, and communicate uncertainty during task execution. We operationalize EH through three trajectory-level behavioral dimensions: _Identify_, _Solve_, and _Escalate_ (ISE). Through _knowledge conflict_, situations where the backbone language model’s parametric knowledge contradicts the evidence it encounters, or where two contextual sources disagree, we build a two-level evaluation framework: (1) controlled single-step conflicts, and (2) naturally occurring conflicts during multi-step agentic executions, each level paired with matched no-conflict controls. Evaluating four agents, we find an inverse relationship between task accuracy and epistemic humility: the most accurate agents are often the most likely to give overconfident answers despite recognizing conflicts or risks. Trajectory-level analysis further reveals that agents frequently detect conflicts in early steps of execution but fail to maintain or resolve them in later steps. Finally, we show that Model-level interventions can improve EH, but often at the cost of task accuracy, suggesting that epistemic humility emerges from the interaction among the backbone model, agent harness, and evaluation environment.
Anthology ID:
2026.findings-emnlp.2128
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
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
45401–45420
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.2128/
DOI:
Bibkey:
Cite (ACL):
Kaiser Sun, Bernal Jiménez Gutiérrez, Hongjun Liu, Jingyu Zhang, Jie Gao, Mark Dredze, and Daniel Khashabi. 2026. Accurate but Not Humble: Evaluating Epistemic Humility in LLM Agents under Knowledge Conflict. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 45401–45420, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Accurate but Not Humble: Evaluating Epistemic Humility in LLM Agents under Knowledge Conflict (Sun et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.2128.pdf