Within the context of reading comprehension, the task of Distractor Generation (DG) aims to generate several incorrect options to confuse readers. Traditional supervised methods for DG rely heavily on expensive human-annotated distractor labels. In this paper, we propose an unsupervised DG framework, leveraging Large Language Models (LLMs) as cost-effective annotators to enhance the DG capability of smaller student models. Specially, to perform knowledge distilling, we propose a dual task training strategy that integrates pseudo distractors from LLMs and the original answer in-formation as the objective targets with a two-stage training process. Moreover, we devise a counterfactual contrastive decoding mechanism for increasing the distracting capability of the DG model. Experiments show that our unsupervised generation method with Bart-base greatly surpasses GPT-3.5-turbo performance with only 200 times fewer model parameters. Our proposed unsupervised DG method offers a cost-effective framework for practical reading comprehension applications, without the need of laborious distractor annotation and costly large-size models

在阅读理解的背景下，我们提出了一种无监督的分心生成框架，利用大型语言模型作为经济高效的注释器来增强较小学生模型的分心生成能力。实验证明，我们提出的无监督生成方法大大超越了GPT-3.5-turbo的性能，而参数只有后者的200倍少。我们的无监督分心生成方法为实际阅读理解应用提供了一种经济高效的框架，无需费力的分心注释和昂贵的大型模型。

通过大型语言模型蒸馏和对抗对比解码进行无监督分心生成