The Personalization Trap: How User Memory Alters Emotional Reasoning in LLMs

Xi Fang, Weijie Xu, Yuchong Zhang, Scott Nickleach, Stephanie Eckman, Chandan K. Reddy


Abstract
When an AI assistant remembers that Sarah is a single mother working two jobs, does it interpret her stress differently than if she were a wealthy executive? As personalized AI systems increasingly incorporate long-term user memory, understanding how this memory shapes emotional reasoning is critical. We investigate how user memory affects emotional intelligence in large language models (LLMs) by evaluating 15 models on human validated emotional intelligence tests. We find that identical scenarios paired with different user profiles produce systematically divergent emotional interpretations. Across validated user-independent emotional scenarios and diverse user profiles, systematic biases emerged in several high-performing LLMs where advantaged profiles received more accurate emotional interpretations. Moreover, LLMs demonstrate significant disparities across demographic factors in emotion understanding and supportive recommendations tasks, indicating that personalization mechanisms can embed social hierarchies into models’ emotional reasoning. These results highlight a key challenge for memory-enhanced AI: systems designed for personalization may inadvertently reinforce social inequalities.
Anthology ID:
2026.acl-short.43
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
ACL
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Publisher:
Association for Computational Linguistics
Note:
Pages:
511–529
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URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-short.43/
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Cite (ACL):
Xi Fang, Weijie Xu, Yuchong Zhang, Scott Nickleach, Stephanie Eckman, and Chandan K. Reddy. 2026. The Personalization Trap: How User Memory Alters Emotional Reasoning in LLMs. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers), pages 511–529, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
The Personalization Trap: How User Memory Alters Emotional Reasoning in LLMs (Fang et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-short.43.pdf
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