DSPA: Dynamic SAE Steering for Data-Efficient Preference Alignment

James Wedgwood, Aashiq Muhamed, Mona T. Diab, Virginia Smith


Abstract
Preference alignment is usually achieved by weight-updating training on preference data, which is costly and provides limited mechanistic visibility. We propose Dynamic SAE Steering for Preference Alignment (DSPA), an inference-time method that makes sparse autoencoder (SAE) steering prompt-conditional. From preference triples, DSPA computes a conditional-difference map linking prompt features to generation-control features; during decoding, it modifies only token-active latents, without base-model weight updates. Across Gemma-2-2B/9B and Qwen3-8B, DSPA improves MT-Bench and is competitive on AlpacaEval while preserving multiple-choice accuracy. Under restricted preference data, DSPA remains robust and can rival heavier alignment pipelines at a fraction of the compute. Finally, we audit the SAE features DSPA modifies, finding that preference directions are dominated by discourse and stylistic signals, and provide theory clarifying the conditional-difference map estimate and when top-k ablation is principled.
Anthology ID:
2026.emnlp-main.169
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:
3879–3898
Language:
URL:
https://aclanthology.org/2026.emnlp-main.169/
DOI:
Bibkey:
Cite (ACL):
James Wedgwood, Aashiq Muhamed, Mona T. Diab, and Virginia Smith. 2026. DSPA: Dynamic SAE Steering for Data-Efficient Preference Alignment. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 3879–3898, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
DSPA: Dynamic SAE Steering for Data-Efficient Preference Alignment (Wedgwood et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.169.pdf