Truth or Tribe: How In-group Favoritism Prioritize Facts in Persona Agents

Shijun Lei, Hongyu Wang, Yunji Liang, Haowen Zheng, Bin Guo, Zhiwen Yu


Abstract
In-group favoritism refers to the phenomenon of favoring members of one’s in-group over out-group members and is widely observed in numerous social cooperative behaviors. Recently, in-group favoritism biases have also been identified in generative language models. However, whether persona agents exhibit in-group favoritism when faced with conflicting information, including misinformation, and how to mitigate its adverse effects remain understudied. To address these problems, we propose a Truth or Tribe simulation framework to study agent cooperation in the spread of conflicting information through a triadic interaction paradigm, and conduct controlled trials to evaluate the primary moderating factors. Extensive results showcase that persona agents display strong in-group favoritism, accepting incorrect answers from identity-similar peers at much higher rates than from dissimilar peers. In-group favoritism continues to emerge in defeasible reasoning contexts where no absolute truth exists, and it intensifies as cognitive complexity increases. Furthermore, three intervention strategies—Identity-Blind Instruction, Structured Counterfactual Reasoning, and Heterogeneous Perspective Ensemble—are proposed to mitigate in-group favoritism.
Anthology ID:
2026.emnlp-main.505
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:
11596–11617
Language:
URL:
https://aclanthology.org/2026.emnlp-main.505/
DOI:
Bibkey:
Cite (ACL):
Shijun Lei, Hongyu Wang, Yunji Liang, Haowen Zheng, Bin Guo, and Zhiwen Yu. 2026. Truth or Tribe: How In-group Favoritism Prioritize Facts in Persona Agents. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 11596–11617, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Truth or Tribe: How In-group Favoritism Prioritize Facts in Persona Agents (Lei et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.505.pdf