StateSwap: Probing Support–Elimination Hidden States in Multiple-Choice Questions

Chao Gao, Haijiang Liu, Qiyuan Li, Caicai Guo, Frank van Harmelen, Jinguang Gu


Abstract
Large language models often answer the same multiple-choice question inconsistently when it is posed under support-oriented and elimination-oriented framings. We investigate whether these discrepancies arise from different internal representations induced by the two framings. We introduce a dual-framing protocol with minimally varied prompts that use either support- or elimination-oriented framing while keeping the evaluation target fixed. To probe the internal computation, we append an untrained special token, [STATE], and treat its residual-stream activation as an intervention interface. Across both models, the two framings induce separable [STATE] activations concentrated in intermediate layers. Swapping these activations between paired prompts systematically changes predictions and improves cross-framing agreement, providing intervention-based evidence that the activations are behaviorally relevant. Beyond instance-level substitution, mean-difference steering directions derived from the dual-framing contrast exhibit more bounded layer-wise responses than matched contrastive activation addition directions under the evaluated protocol.
Anthology ID:
2026.findings-emnlp.300
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:
6343–6364
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.300/
DOI:
Bibkey:
Cite (ACL):
Chao Gao, Haijiang Liu, Qiyuan Li, Caicai Guo, Frank van Harmelen, and Jinguang Gu. 2026. StateSwap: Probing Support–Elimination Hidden States in Multiple-Choice Questions. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 6343–6364, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
StateSwap: Probing Support–Elimination Hidden States in Multiple-Choice Questions (Gao et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.300.pdf