SAEExplainer: Interpreting SAE Features with Activation-Guided Preference Optimization

Jingyi He, Haiyan Zhao, Ruxue Shi, Yanguang Liu, Xin Wang, Fei Sun, Mengnan Du


Abstract
Although Sparse Autoencoders (SAEs) have mitigated the opacity of large language models (LLMs) by decomposing dense representations into sparse features, explaining these features still remains a central challenge. Current explanation methods, however, typically operate within an open-loop paradigm, failing to leverage mechanistic feedback for further refinement. In this paper, we propose SAEExplainer, a training framework that utilizes activation scores as an objective reward signal to train the model for self-correction and iterative bootstrapping. By iteratively verifying and correcting foundational explanations through a two-round optimization process, SAEExplainer achieves continuous improvement in its explanatory capabilities. This mechanism significantly reduces explanation hallucinations and reinforces causal triggering patterns. Extensive experiments demonstrate our approach improves upon established baselines across most metrics, especially in causal triggering and discriminative activation. The code is available at https://github.com/he-jingyi/SAEExplainer.
Anthology ID:
2026.emnlp-main.393
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:
9019–9038
Language:
URL:
https://aclanthology.org/2026.emnlp-main.393/
DOI:
Bibkey:
Cite (ACL):
Jingyi He, Haiyan Zhao, Ruxue Shi, Yanguang Liu, Xin Wang, Fei Sun, and Mengnan Du. 2026. SAEExplainer: Interpreting SAE Features with Activation-Guided Preference Optimization. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 9019–9038, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
SAEExplainer: Interpreting SAE Features with Activation-Guided Preference Optimization (He et al., EMNLP 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.emnlp-main.393.pdf