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arXiv 2506.02592cs.CL

超越表面:测量LLM评判中的自我偏好

Beyond the Surface: Measuring Self-Preference in LLM Judgments

Gaoling School of Artificial Intelligence, Renmin University of China(中国人民大学首都人工智能学院);Huawei Poisson Lab(华为Poisson实验室);Beijing Key Laboratory of Research on Large Models and Intelligent Governance(北京大型模型与智能治理重点实验室)

Zhi-Yuan Chen, Hao Wang, Xinyu Zhang, Enrui Hu, Yankai Lin

AI总结:

本文提出DBG分数,利用黄金评判分离回答质量与自我偏好偏差,系统测量不同LLM的自我偏好偏差,并分析其影响因素与注意力机制层面的成因。

摘要:

近期研究表明,大型语言模型(LLMs)在担任评判者时会表现出自我偏好偏差,即它们倾向于偏爱自己生成的回答,而非其他模型生成的回答。现有方法通常通过计算评判模型给自己回答所打分数与给其他模型回答所打分数的差值来衡量这种偏差。然而,这种方法将自我偏好偏差与回答质量混为一谈,因为即使不存在偏差,评判模型生成的更高质量回答也可能导致正分数差值。为解决这一问题,我们引入黄金评判作为回答实际质量的代理,并提出DBG分数,该分数将自我偏好偏差衡量为评判模型给自己回答所打分数与相应黄金评判之间的差值。由于黄金评判反映了真实回答质量,DBG分数减轻了回答质量对偏差测量的混淆效应。利用DBG分数,我们进行了全面实验,以评估不同版本、规模和推理能力的LLM中的自我偏好偏差。此外,我们研究了两个影响并有助于减轻自我偏好偏差的因素:回答文本风格和评判模型的后训练数据。最后,我们从基于注意力的视角探索了自我偏好偏差的潜在底层机制。我们的代码和数据可在https://github.com/zhiyuanc2001/self-preference获取。

英文摘要:

Recent studies show that large language models (LLMs) exhibit self-preference bias when serving as judges, meaning they tend to favor their own responses over those generated by other models. Existing methods typically measure this bias by calculating the difference between the scores a judge model assigns to its own responses and those it assigns to responses from other models. However, this approach conflates self-preference bias with response quality, as higher-quality responses from the judge model may also lead to positive score differences, even in the absence of bias. To address this issue, we introduce gold judgments as proxies for the actual quality of responses and propose the DBG score, which measures self-preference bias as the difference between the scores assigned by the judge model to its own responses and the corresponding gold judgments. Since gold judgments reflect true response quality, the DBG score mitigates the confounding effect of response quality on bias measurement. Using the DBG score, we conduct comprehensive experiments to assess self-preference bias across LLMs of varying versions, sizes, and reasoning abilities. Additionally, we investigate two factors that influence and help alleviate self-preference bias: response text style and the post-training data of judge models. Finally, we explore potential underlying mechanisms of self-preference bias from an attention-based perspective. Our code and data are available at https://github.com/zhiyuanc2001/self-preference.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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