Attention-Guided Layer Selection for Contrastive Decoding in Large Language Models

Yusuke Sakai, Natthawut Kertkeidkachorn, Kiyoaki Shirai


Abstract
Contrastive decoding methods such as DoLa improve the factuality of Large Language Models (LLMs) by contrasting the output distributions of mature and premature layers. However, DoLa’s dynamic layer selection relies solely on divergences in output vocabulary distributions. In this work, we propose three attention-guided strategies—Attention-JSD, Attention-Entropy-Max, and Attention-Entropy-Min—that leverage structural information carried by internal self-attention mechanisms as a signal for layer selection. Experimental results on TruthfulQA demonstrate that our strategies, particularly Attention-JSD and Attention-Entropy-Min, consistently outperform the original DoLa. We observe significant gains on multi-answer metrics (MC2 and MC3), suggesting that attention distributions can provide a more sensitive signal for resolving factual knowledge than output vocabulary distributions.
Anthology ID:
2026.aacl-long.18
Volume:
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venues:
AACL | IJCNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
351–363
Language:
URL:
https://aclanthology.org/2026.aacl-long.18/
DOI:
Bibkey:
Cite (ACL):
Yusuke Sakai, Natthawut Kertkeidkachorn, and Kiyoaki Shirai. 2026. Attention-Guided Layer Selection for Contrastive Decoding in Large Language Models. In Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers), pages 351–363, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
Attention-Guided Layer Selection for Contrastive Decoding in Large Language Models (Sakai et al., AACL-IJCNLP 2026)
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PDF:
https://aclanthology.org/2026.aacl-long.18.pdf