Behavior Carries Over: An AI Sandbagging Detection Method Inspired by Honest Inertia

Junjie Chu, Mingjie Li, Zeyuan Chen, Ye Leng, Yisen Wang, Michael Backes, Yang Zhang


Abstract
Reliable capability assessment is essential for governing and securely deploying advanced AI systems. However, "AI Sandbagging," where models strategically suppress their true capabilities during evaluation, undermines existing assessment frameworks by making it difficult to distinguish genuine limitations from strategic concealment. To address this challenge, we propose a new black-box sandbag detection method inspired by "honesty inertia," a psychological phenomenon where humans struggle to maintain deception after answering simple questions truthfully. We hypothesize that large language models exhibit an analogous effect: inserting several simple, unrelated questions, which target models should answer correctly, before the target query induces honest inertia, causing sandbag models to involuntarily increase accuracy while standard models remain stable. Through extensive experiments on multiple datasets with various model architectures, we confirm the validity of this hypothesis and establish this differential response as a reliable, model-independent sandbag detection signal. We further provide interpretability support for this phenomenon from two dimensions: theoretical derivation and hidden state analysis of models. This work offers a practical tool for enhancing AI audit and supervision.
Anthology ID:
2026.findings-emnlp.2154
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:
46083–46099
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.2154/
DOI:
Bibkey:
Cite (ACL):
Junjie Chu, Mingjie Li, Zeyuan Chen, Ye Leng, Yisen Wang, Michael Backes, and Yang Zhang. 2026. Behavior Carries Over: An AI Sandbagging Detection Method Inspired by Honest Inertia. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 46083–46099, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Behavior Carries Over: An AI Sandbagging Detection Method Inspired by Honest Inertia (Chu et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.2154.pdf