Chameleon LLMs: User Personas Influence Chatbot Personality Shifts

Jane Xing, Tianyi Niu, Shashank Srivastava


Abstract
As large language models (LLMs) integrate into society, their ability to adapt to users is as critical as their accuracy. While prior work has used personality tests to examine the perceived personalities of LLMs, little research has explored whether LLMs adapt their perceived personalities in response to user interactions. We investigate whether and how LLMs exhibit conversational adaptations over prolonged interactions. Using a controlled simulations where a user and chatbot engage in dialogue, we measure the chatbot’s personality shift before and after the conversation. Across multiple models, we find that traits such as Agreeableness, Extraversion, and Conscientiousness are highly susceptible to user influence, whereas Emotional Stability and Intellect remain relatively more stable. Our results suggest that LLMs dynamically adjust their conversational style in response to user personas, raising important implications for AI alignment, trust, and safety.
Anthology ID:
2025.emnlp-main.875
Volume:
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Christos Christodoulopoulos, Tanmoy Chakraborty, Carolyn Rose, Violet Peng
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
17325–17343
Language:
URL:
https://preview.aclanthology.org/ingest-emnlp/2025.emnlp-main.875/
DOI:
Bibkey:
Cite (ACL):
Jane Xing, Tianyi Niu, and Shashank Srivastava. 2025. Chameleon LLMs: User Personas Influence Chatbot Personality Shifts. In Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing, pages 17325–17343, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
Chameleon LLMs: User Personas Influence Chatbot Personality Shifts (Xing et al., EMNLP 2025)
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https://preview.aclanthology.org/ingest-emnlp/2025.emnlp-main.875.pdf
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