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arXiv 2606.03437cs.CL
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大型语言模型对自己的回答过度自信

Large Language Models Are Overconfident in Their Own Responses

Johannes Gutenberg University Mainz(莱茵河畔明斯特约翰·古腾堡大学);University of Colorado Boulder(科罗拉多大学波德分校)

Mario Sanz-Guerrero, Manuel Mager, Katharina von der Wense

AI总结:

研究指令微调与聊天模板导致的大型语言模型校准偏差,发现“所有权偏见”使模型对自己的回答自信度高出26%,并提出通过将模型回答伪装为用户输入来降低过度自信。

摘要:

先前工作表明,指令微调的大型语言模型(LLMs)比其基础预训练模型校准更差。然而,关于常用聊天模板对对话型LLM校准的影响知之甚少。在本工作中,我们通过解耦后训练算法和聊天格式的影响,研究了导致这种校准偏差的机制。我们发现,虽然指令微调从根本上损害了校准,但聊天模板通过“所有权偏见”加剧了问题——模型对自己回答的自信度显著高于对用户提供的相同回答的自信度。在六个近期开源权重LLM、三个基准和三种置信度获取方法上的大量实验表明,模型对自己的回答分配的置信度高出26%。利用这一见解,我们提出一种简单的推理时策略:在置信度获取时将模型的回答框定为用户输入。该方法显著降低了过度自信,并将校准提高了26%,无需重新训练,缩小了基础模型与指令微调模型之间的差距。

英文摘要:

Prior work has shown that instruction-tuned large language models (LLMs) are less well calibrated than their base pre-trained counterparts. However, little is known about the frequently used chat template's effect on the calibration of conversational LLMs. In this work, we investigate the mechanisms driving this miscalibration by decoupling the effects of the post-training algorithm and the chat format. We find that, while instruction tuning fundamentally harms calibration, the chat template aggravates the issue through an "ownership bias" -- models are significantly more confident in their own answers than in identical answers provided by a user. Extensive experiments across six recent open-weight LLMs, three benchmarks, and three confidence elicitation methods show that models assign up to 26% higher confidence to their own responses. Leveraging this insight, we propose a simple inference-time strategy: framing the model's answer as user input during confidence elicitation. This approach significantly reduces overconfidence and improves calibration by up to 26% without the need for retraining, narrowing the gap between base and instruction-tuned models.

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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