Accounting for Sycophancy in Language Model Uncertainty Estimation

Anthony Sicilia, Mert Inan, Malihe Alikhani


Abstract
Effective human-machine collaboration requires machine learning models to externalize uncertainty, so users can reflect and intervene when necessary. For language models, these representations of uncertainty may be impacted by sycophancy bias: proclivity to agree with users, even if they are wrong. For instance, models may be over-confident in (incorrect) problem solutions suggested by a user. We study the relationship between sycophancy and uncertainty estimation for the first time. We propose a generalization of the definition of sycophancy bias to measure downstream impacts on uncertainty estimation, and also propose a new algorithm (SyRoUP) to account for sycophancy in the uncertainty estimation process. Unlike previous works, we study a broad array of user behaviors, varying both correctness and confidence of user suggestions to see how model answers (and their certainty) change. Our experiments across conversation forecasting and question-answering tasks show that user confidence plays a critical role in modulating the effects of sycophancy, and that SyRoUP can better predict these effects. From these results, we argue that externalizing both model and user uncertainty can help to mitigate the impacts of sycophancy bias.
Anthology ID:
2025.findings-naacl.438
Volume:
Findings of the Association for Computational Linguistics: NAACL 2025
Month:
April
Year:
2025
Address:
Albuquerque, New Mexico
Editors:
Luis Chiruzzo, Alan Ritter, Lu Wang
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
7851–7866
Language:
URL:
https://preview.aclanthology.org/fix-sig-urls/2025.findings-naacl.438/
DOI:
Bibkey:
Cite (ACL):
Anthony Sicilia, Mert Inan, and Malihe Alikhani. 2025. Accounting for Sycophancy in Language Model Uncertainty Estimation. In Findings of the Association for Computational Linguistics: NAACL 2025, pages 7851–7866, Albuquerque, New Mexico. Association for Computational Linguistics.
Cite (Informal):
Accounting for Sycophancy in Language Model Uncertainty Estimation (Sicilia et al., Findings 2025)
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PDF:
https://preview.aclanthology.org/fix-sig-urls/2025.findings-naacl.438.pdf