Mechanism Alignment for Socially Embedded Decision Making in LLMs

Jiaxin Liu, Yuhe Wu, Yixuan Xie, Hanzhi Xiao, Zeyu ma, Wenqing GU, Zeheng Xian, Guang Zhang


Abstract
LLM agents are widely used in social simulation, yet fluent social reasoning does not guarantee valid decision mechanisms. We test whether models implement socially embedded utility, where actions depend on peer-weighted references rather than isolated private preference. We introduce a theory-guided benchmark from network utility theory covering utility recovery, social-comparison gating, and structural transfer across two out-of-distribution decision forms. Across open-source and proprietary models, we find a gap between cue recognition and peer aggregation, spurious social activation when comparison should be inactive, and declining accuracy as social dependence rises. We propose theory-supervised mechanism alignment trained on latent utility states. Fine-tuning yields +8.3 and +13.9 utility-recovery points on Llama-3.1-8B and Qwen3-8B, raises gating above 95%, and improves transfer to unseen structures. Multi-agent simulations show that repairing local utility shifts macro outcomes, including stronger financial amplification and more stable labor stratification, which indicates that realistic macro-level simulations require adjustments at the individual level. Data and code are available at https://github.com/saaranLiu/SEDM-alignment.
Anthology ID:
2026.emnlp-main.468
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:
10759–10779
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URL:
https://aclanthology.org/2026.emnlp-main.468/
DOI:
Bibkey:
Cite (ACL):
Jiaxin Liu, Yuhe Wu, Yixuan Xie, Hanzhi Xiao, Zeyu ma, Wenqing GU, Zeheng Xian, and Guang Zhang. 2026. Mechanism Alignment for Socially Embedded Decision Making in LLMs. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 10759–10779, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Mechanism Alignment for Socially Embedded Decision Making in LLMs (Liu et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.468.pdf