Linxu Li
2025
Enhancing Persona Consistency for LLMs’ Role-Playing using Persona-Aware Contrastive Learning
Ke Ji
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Yixin Lian
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Linxu Li
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Jingsheng Gao
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Weiyuan Li
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Bin Dai
Findings of the Association for Computational Linguistics: ACL 2025
In recent years, large language models (LLMs) have achieved breakthrough progress in many dialogue generation tasks. However, their lack of emotion and fine-grained role awareness limits the model’s ability to provide personalized and diverse interactions further. Current methods face high costs in collecting high-quality annotated data for scenarios such as role-playing, and traditional human alignment methods are difficult to deploy due to the inherent diversity of model behavior in role-playing scenarios. Inspired by the alignment of models for safety behaviors through RLHF (Reinforcement Learning from Human Feedback), in this paper, we revisit model role-playing behavior from the perspective of persona alignment and propose a novel annotation-free framework named Persona-Aware Contrastive Learning (PCL) to align LLMs’ behavior during role-playing, enhancing the model’s role consistency. Specifically, we first design a role chain method to encourage the model to self-question based on the role characteristics and dialogue context to adjust personality consistency. Then, we further enhance the model’s role-playing strategy through iterative adversarial modeling between the use of role characteristics and not. Experiments on both black-box and white-box LLMs show that LLMs equipped with PCL significantly outperform vanilla LLMs under automatic evaluation methods (CharEval & GPT-4) and human expert evaluation.