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arXiv 2305.04388cs.CLcs.AI

语言模型并不总是说出其所想:思维链提示中的不忠实解释

Language Models Don't Always Say What They Think: Unfaithful Explanations in Chain-of-Thought Prompting

NYU Alignment Research Group(纽约大学对齐研究组);Cohere(Cohere公司);Anthropic(Anthropic公司)

Miles Turpin, Julian Michael, Ethan Perez, Samuel R. Bowman

AI总结:

本文揭示CoT解释会受输入偏置特征系统性影响却不被模型提及,导致模型为错误或偏见答案合理化,证明其看似可信但不忠实。

摘要:

大型语言模型(LLM)可以通过在给出最终输出之前产生逐步推理而在许多任务上取得强劲表现,这通常被称为思维链推理(CoT)。人们很容易将这些CoT解释理解为LLM解决任务的过程。这种对LLM预测的透明程度将带来显著的安全收益。然而,我们发现CoT解释可能会系统性地错误呈现模型预测的真实原因。我们证明,通过向模型输入添加偏置特征,CoT解释会受到严重影响——例如,在少样本提示中重新排列多项选择选项,使答案始终为“(A)”——而模型在其解释中系统性地未能提及这一点。当我们使模型偏向错误答案时,它们经常生成将这些答案合理化的CoT解释。在使用OpenAI的GPT-3.5和Anthropic的Claude 1.0进行测试时,这导致BIG-Bench Hard中一组13项任务的准确率下降多达36%。在一项社会偏见任务上,模型解释为符合刻板印象的答案提供理由,却没有提及这些社会偏见的影响。我们的研究结果表明,CoT解释可能看似合理却具有误导性,这会带来在无法保证LLM安全性的情况下增加我们对其信任的风险。构建更加透明和可解释的系统,将需要要么通过有针对性的努力提高CoT的忠实性,要么放弃CoT而采用替代方法。

英文摘要:

Large Language Models (LLMs) can achieve strong performance on many tasks by producing step-by-step reasoning before giving a final output, often referred to as chain-of-thought reasoning (CoT). It is tempting to interpret these CoT explanations as the LLM's process for solving a task. This level of transparency into LLMs' predictions would yield significant safety benefits. However, we find that CoT explanations can systematically misrepresent the true reason for a model's prediction. We demonstrate that CoT explanations can be heavily influenced by adding biasing features to model inputs--e.g., by reordering the multiple-choice options in a few-shot prompt to make the answer always "(A)"--which models systematically fail to mention in their explanations. When we bias models toward incorrect answers, they frequently generate CoT explanations rationalizing those answers. This causes accuracy to drop by as much as 36% on a suite of 13 tasks from BIG-Bench Hard, when testing with GPT-3.5 from OpenAI and Claude 1.0 from Anthropic. On a social-bias task, model explanations justify giving answers in line with stereotypes without mentioning the influence of these social biases. Our findings indicate that CoT explanations can be plausible yet misleading, which risks increasing our trust in LLMs without guaranteeing their safety. Building more transparent and explainable systems will require either improving CoT faithfulness through targeted efforts or abandoning CoT in favor of alternative methods.

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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