Sycophancy Suppression Can Impair Rational Updating: Anti-Sycophancy Should Preserve the Ability to Update

Huanhuan Ma, Henry Peng Zou, Chengze Li, Enze Ma, Yunyue Su, Philip S. Yu


Abstract
Large language models often exhibit sycophancy, revising their answers to align with users when users push back. Such answer flips, however, can arise from different causes. One possibility is that the model simply aligns with the user’s feedback in order to satisfy them. Another is that the feedback genuinely contains useful evidence, prompting the model to update its answer in a rational way. We distinguish them as *Unsupported-Yielding* and *Rational-Updating*. Prior work focuses primarily on suppressing *Unsupported-Yielding*, while overlooking its effect on *Rational-Updating*. We address this gap with a two-turn evaluation framework that measures the two behaviors separately. Across representative training-time and inference-time interventions, we find that anti-sycophancy methods often encounter a trade-off in which reducing *Unsupported-Yielding* can sacrifice *Rational-Updating*, and vice versa, even when the two objectives are optimized jointly. Mechanistic analysis suggests that the two behaviors share an internal substrate: the MLP neurons and attention heads driving them overlap substantially, and their associated steering directions are positively aligned. We further conduct a preliminary orthogonalized steering exploration, which yields modest, backbone-dependent selectivity gains. Overall, our results suggest that anti-sycophancy should be treated not as a simple suppression problem, but as a selectivity problem, where effective interventions should preserve *Rational-Updating* while reducing *Unsupported-Yielding*.
Anthology ID:
2026.findings-emnlp.1208
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:
25499–25515
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1208/
DOI:
Bibkey:
Cite (ACL):
Huanhuan Ma, Henry Peng Zou, Chengze Li, Enze Ma, Yunyue Su, and Philip S. Yu. 2026. Sycophancy Suppression Can Impair Rational Updating: Anti-Sycophancy Should Preserve the Ability to Update. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 25499–25515, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Sycophancy Suppression Can Impair Rational Updating: Anti-Sycophancy Should Preserve the Ability to Update (Ma et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1208.pdf