Faithful Persona Steering under Incongruity via Dual-Stream Refinement

Yu-An Chu, Jen-Ren Pong, Chia-Yao Yeh, Meng-Fen Chiang


Abstract
Standard LLM personalization typically frames identity as a static retrieval task, overlooking the inherent incongruity of human personas, where stable traits coexist with atypical, context-specific stances. Existing methods struggle to reconcile these dimensions: prompting succumbs to context drift over long sequences, while fine-tuning often suppresses idiosyncratic “quirks” in favor of generic distributional patterns. To bridge this gap, we present QuirkyMind, a framework that disentangles identity definition from its expression. First, Traits Anchoring constructs a dual-stream latent state, fusing a sentence-level summary for semantic stability with a token-level sequence for generative control. This state is stabilized via In-Context Narrative Refinement using an alternating objective: a discriminative InfoNCE loss anchors the persona in representation space to prevent drift, while a generative cross-entropy loss ensures faithful verbalization. Finally, Persona Steered Generalization transfers the refined state to downstream tasks via parameter-efficient adapters. Empirical evaluations on Persona-Steered QA and Narrative Inference demonstrate that QuirkyMind mitigates drift, consolidating persona knowledge without erasing authentic incongruities.
Anthology ID:
2026.findings-acl.1205
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
24078–24095
Language:
URL:
https://aclanthology.org/2026.findings-acl.1205/
DOI:
Bibkey:
Cite (ACL):
Yu-An Chu, Jen-Ren Pong, Chia-Yao Yeh, and Meng-Fen Chiang. 2026. Faithful Persona Steering under Incongruity via Dual-Stream Refinement. In Findings of the Association for Computational Linguistics: ACL 2026, pages 24078–24095, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Faithful Persona Steering under Incongruity via Dual-Stream Refinement (Chu et al., Findings 2026)
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https://aclanthology.org/2026.findings-acl.1205.pdf
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