Prototype-Based Dynamic Steering for Large Language Models

Ceyhun Efe Kayan, Li Zhang


Abstract
Despite impressive breadth, LLMs still rely on explicit reasoning instructions or static, one-fits-all steering methods, leaving a gap for adaptive, instruction-free reasoning amplification. We present Prototype-Based Dynamic Steering (PDS), a test-time method that amplifies large language model (LLM) reasoning without adding or altering instructions. We introduce “reasoning prototypes” by clustering activation differences between Chain-of-Thought (CoT) and neutral prompts. At inference, an input’s hidden state is projected onto these prototypes to form an instance-specific steering vector. Evaluated on GSM8K, AQuA-RAT, and BIG-Bench tasks, PDS consistently improves accuracy without fine-tuning or prompt engineering. Notably, the gains persist even when CoT is explicitly suppressed to improve cost-efficiency, indicating that the intervention strengthens latent reasoning processes rather than inducing a superficial behavioral shift. These results position dynamic, prototype-guided steering as a lightweight alternative to training-time approaches for enhancing LLM reasoning.
Anthology ID:
2026.emnlp-main.2442
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
55412–55425
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2442/
DOI:
Bibkey:
Cite (ACL):
Ceyhun Efe Kayan and Li Zhang. 2026. Prototype-Based Dynamic Steering for Large Language Models. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 55412–55425, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Prototype-Based Dynamic Steering for Large Language Models (Kayan & Zhang, EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.2442.pdf