When Correct Beliefs Collapse: Epistemic Resilience of LLMs under Clinical Pressure

Fuente: arXiv
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Autores principales: Xiao, Boyu, Tian, Xiuqi, Song, Xuwen, Wang, Haochun, Song, Guanchun, Zhao, Sendong, Qin, Bing
Formato: Preprint
Publicado: 2026
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author Xiao, Boyu
Tian, Xiuqi
Song, Xuwen
Wang, Haochun
Song, Guanchun
Zhao, Sendong
Qin, Bing
author_facet Xiao, Boyu
Tian, Xiuqi
Song, Xuwen
Wang, Haochun
Song, Guanchun
Zhao, Sendong
Qin, Bing
contents Despite strong medical benchmark accuracy, LLMs can exhibit severe multi-turn sycophancy in clinical dialogue, abandoning initial correct diagnosis under escalating pressure. We propose \textbf{\textsc{Med-Stress}}, a targeted stress test framework that evaluates belief stability under escalating pressure. Across nine frontier large language models (LLMs), we find a clear dissociation between medical knowledge and robustness: high initial diagnostic capability does not imply high belief stability, yielding large knowledge-robustness gaps for several LLMs. To mitigate this failure mode, we propose a lightweight inference-time defense, \textbf{\texttt{RBED}} (\textbf{R}ole-\textbf{B}ased \textbf{E}pistemic \textbf{D}efense), and \textbf{\texttt{R-FT}} (\textbf{R}esilience-oriented \textbf{F}ine-\textbf{T}uning), a training-time approach that internalizes evidence-based resistance to pressure. Experiments show that \textbf{\texttt{R-FT}} nearly eliminates belief change and substantially improves robustness.
format Preprint
id arxiv_https___arxiv_org_abs_2605_23932
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle When Correct Beliefs Collapse: Epistemic Resilience of LLMs under Clinical Pressure
Xiao, Boyu
Tian, Xiuqi
Song, Xuwen
Wang, Haochun
Song, Guanchun
Zhao, Sendong
Qin, Bing
Artificial Intelligence
Computation and Language
Computers and Society
Machine Learning
Despite strong medical benchmark accuracy, LLMs can exhibit severe multi-turn sycophancy in clinical dialogue, abandoning initial correct diagnosis under escalating pressure. We propose \textbf{\textsc{Med-Stress}}, a targeted stress test framework that evaluates belief stability under escalating pressure. Across nine frontier large language models (LLMs), we find a clear dissociation between medical knowledge and robustness: high initial diagnostic capability does not imply high belief stability, yielding large knowledge-robustness gaps for several LLMs. To mitigate this failure mode, we propose a lightweight inference-time defense, \textbf{\texttt{RBED}} (\textbf{R}ole-\textbf{B}ased \textbf{E}pistemic \textbf{D}efense), and \textbf{\texttt{R-FT}} (\textbf{R}esilience-oriented \textbf{F}ine-\textbf{T}uning), a training-time approach that internalizes evidence-based resistance to pressure. Experiments show that \textbf{\texttt{R-FT}} nearly eliminates belief change and substantially improves robustness.
title When Correct Beliefs Collapse: Epistemic Resilience of LLMs under Clinical Pressure
topic Artificial Intelligence
Computation and Language
Computers and Society
Machine Learning
url https://arxiv.org/abs/2605.23932