You Only Align Once: Propagating Cooperative Behaviors in Multi-Agent Systems through Seed Agents

Nicole Summer Hsing, Asuka Yuxi Zheng, Yi Zhao, Haoqin Tu, Jen-tse Huang


Abstract
Ensuring aligned agent behaviors in distributed open multi-agent systems remains challenging, especially as populations grow and unaligned agents may exist. We show that a single aligned agent can propagate cooperative behaviors to unmodified agents purely through natural-language interaction, a phenomenon we term Alignment Propagation. We study this in the Red-Black Game, a team-based iterated Prisoner’s Dilemma in which teammates deliberate and vote to determine their team’s collective action. By distilling the cooperative reasoning and persuasive dialogues of a teacher model into Qwen3-14B, we obtain a seed agent that, when placed among four unmodified teammates, more than doubles the cooperation rate from 24.8% to 62.2%, outperforming the teacher model and a vanilla Gemini-3.1-Pro. Remarkably, a seed trained exclusively on the Red-Black Game transfers zero-shot to Sugarscape, a spatially grounded survival simulation with pairwise trading, achieving a 91.5% trade success rate versus a 21.6% baseline. Our results reframe multi-agent alignment from an exhaustive per-agent training problem to a scalable social capability that can be engineered through strategic seed placement.
Anthology ID:
2026.emnlp-main.218
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:
4999–5036
Language:
URL:
https://aclanthology.org/2026.emnlp-main.218/
DOI:
Bibkey:
Cite (ACL):
Nicole Summer Hsing, Asuka Yuxi Zheng, Yi Zhao, Haoqin Tu, and Jen-tse Huang. 2026. You Only Align Once: Propagating Cooperative Behaviors in Multi-Agent Systems through Seed Agents. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 4999–5036, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
You Only Align Once: Propagating Cooperative Behaviors in Multi-Agent Systems through Seed Agents (Hsing et al., EMNLP 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.emnlp-main.218.pdf