arXiv:2509.18535cs.CLeess.SP2025-09被引 1

用句子结构检测AI生成文本,抗改写、轻量高效。

Trace Is In Sentences: Unbiased Lightweight ChatGPT-Generated Text Detector

  • 基于句子内部结构而非词语,避免被改写绕过
  • 在两个数据集上准确率超90%,且对修改文本保持稳定
  • 适合需要快速部署的反作弊系统或内容审核场景

ChatGPT的广泛使用引发对其滥用的担忧,亟需可靠的AI生成文本检测方法。现有词级检测器易受改写或简单提示(PSP)影响,受模型自身词级模式(CWP)和训练数据偏见干扰,对修改文本性能下降,且常需大型模型或在线LLM交互。为此,我们提出新任务:检测原始及经PSP修改的AI生成文本,并设计轻量级框架,通过编码预训练语言模型的句子嵌入并建模其关系实现分类,其内部结构在词级变化下保持不变。采用对比学习缓解自回归生成带来的嵌入偏见,并引入因果图与反事实方法,剥离主题相关偏见,分离出结构性特征。在两个精心构建的数据集(包括摘要对比和修订版生活问答)上的实验验证了该方法的有效性。

原文摘要 · Abstract (English)

The widespread adoption of ChatGPT has raised concerns about its misuse, highlighting the need for robust detection of AI-generated text. Current word-level detectors are vulnerable to paraphrasing or simple prompts (PSP), suffer from biases induced by ChatGPT's word-level patterns (CWP) and training data content, degrade on modified text, and often require large models or online LLM interaction. To tackle these issues, we introduce a novel task to detect both original and PSP-modified AI-generated texts, and propose a lightweight framework that classifies texts based on their internal structure, which remains invariant under word-level changes. Our approach encodes sentence embeddings from pre-trained language models and models their relationships via attention. We employ contrastive learning to mitigate embedding biases from autoregressive generation and incorporate a causal graph with counterfactual methods to isolate structural features from topic-related biases. Experiments on two curated datasets, including abstract comparisons and revised life FAQs, validate the effectiveness of our method.

文本检测轻量模型因果分析

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