@inproceedings{wu-etal-2026-chameleons,
title = "Chameleons and Guardians: Unveiling the Divergence in Personality Plasticity and Cognitive Resistance across {LLM}s",
author = "Wu, Jiaxin and
Zhao, Jie and
Huangxinrong and
Zhang, Cuihong and
Wu, Xiuzhu",
editor = "Liakata, Maria and
Moreira, Viviane P. and
Zhang, Jiajun and
Jurgens, David",
booktitle = "Findings of the {A}ssociation for {C}omputational {L}inguistics: {ACL} 2026",
month = jul,
year = "2026",
address = "San Diego, California, United States",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2026.findings-acl.205/",
pages = "4215--4238",
ISBN = "979-8-89176-395-1",
abstract = "Whether the personality of LLMs can be intentionally reshaped remains controversial. Existing studies often limited to small models, argue for its immutability. Crucially, prior studies fail to uncover that different LLMs exhibit significant compliance divergence when exposed to personality-inducing contexts. To bridge this gap, we introduce Personality Induction Framework (PIF), which systematically reshapes the personality of different LLMs via multi-agent collaboration. Specifically, via Generator-Judge agents, PIF paraphrases MBTI questions to create semantically equivalent but expressively diverse inducing contexts, enabling LLMs to learn personality patterns instead of superficial token matching. Also, PIF achieves fine-grained personality modulation by controlling the intensity of inducing contexts. Extensive experiments on worldwide mainstream LLMs show that PIF reliably transforms their original personalities into desired target personalities. Notably, we find that the outputs of most Western LLMs behave like ``Chameleons'', exhibiting high personality plasticity; whereas the outputs of most Eastern LLMs act as ``Guardians'', manifesting pronounced cognitive resistance. Strikingly, extreme induction intensity (100{\%}) triggers a counter-intuitive ``Alignment Rebound'' in Guardians, resulting in the opposite direction rather than compliance. These findings suggest that LLM personality is a dynamic equilibrium shaped by the trade-off between instruction compliance and cognitive resistance."
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<abstract>Whether the personality of LLMs can be intentionally reshaped remains controversial. Existing studies often limited to small models, argue for its immutability. Crucially, prior studies fail to uncover that different LLMs exhibit significant compliance divergence when exposed to personality-inducing contexts. To bridge this gap, we introduce Personality Induction Framework (PIF), which systematically reshapes the personality of different LLMs via multi-agent collaboration. Specifically, via Generator-Judge agents, PIF paraphrases MBTI questions to create semantically equivalent but expressively diverse inducing contexts, enabling LLMs to learn personality patterns instead of superficial token matching. Also, PIF achieves fine-grained personality modulation by controlling the intensity of inducing contexts. Extensive experiments on worldwide mainstream LLMs show that PIF reliably transforms their original personalities into desired target personalities. Notably, we find that the outputs of most Western LLMs behave like “Chameleons”, exhibiting high personality plasticity; whereas the outputs of most Eastern LLMs act as “Guardians”, manifesting pronounced cognitive resistance. Strikingly, extreme induction intensity (100%) triggers a counter-intuitive “Alignment Rebound” in Guardians, resulting in the opposite direction rather than compliance. These findings suggest that LLM personality is a dynamic equilibrium shaped by the trade-off between instruction compliance and cognitive resistance.</abstract>
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%0 Conference Proceedings
%T Chameleons and Guardians: Unveiling the Divergence in Personality Plasticity and Cognitive Resistance across LLMs
%A Wu, Jiaxin
%A Zhao, Jie
%A Zhang, Cuihong
%A Wu, Xiuzhu
%Y Liakata, Maria
%Y Moreira, Viviane P.
%Y Zhang, Jiajun
%Y Jurgens, David
%A Huangxinrong
%S Findings of the Association for Computational Linguistics: ACL 2026
%D 2026
%8 July
%I Association for Computational Linguistics
%C San Diego, California, United States
%@ 979-8-89176-395-1
%F wu-etal-2026-chameleons
%X Whether the personality of LLMs can be intentionally reshaped remains controversial. Existing studies often limited to small models, argue for its immutability. Crucially, prior studies fail to uncover that different LLMs exhibit significant compliance divergence when exposed to personality-inducing contexts. To bridge this gap, we introduce Personality Induction Framework (PIF), which systematically reshapes the personality of different LLMs via multi-agent collaboration. Specifically, via Generator-Judge agents, PIF paraphrases MBTI questions to create semantically equivalent but expressively diverse inducing contexts, enabling LLMs to learn personality patterns instead of superficial token matching. Also, PIF achieves fine-grained personality modulation by controlling the intensity of inducing contexts. Extensive experiments on worldwide mainstream LLMs show that PIF reliably transforms their original personalities into desired target personalities. Notably, we find that the outputs of most Western LLMs behave like “Chameleons”, exhibiting high personality plasticity; whereas the outputs of most Eastern LLMs act as “Guardians”, manifesting pronounced cognitive resistance. Strikingly, extreme induction intensity (100%) triggers a counter-intuitive “Alignment Rebound” in Guardians, resulting in the opposite direction rather than compliance. These findings suggest that LLM personality is a dynamic equilibrium shaped by the trade-off between instruction compliance and cognitive resistance.
%U https://aclanthology.org/2026.findings-acl.205/
%P 4215-4238
Markdown (Informal)
[Chameleons and Guardians: Unveiling the Divergence in Personality Plasticity and Cognitive Resistance across LLMs](https://aclanthology.org/2026.findings-acl.205/) (Wu et al., Findings 2026)
ACL