🤖 AI Summary
Existing fake news detection methods overly rely on static pattern matching and lack rigorous evaluation of models’ dynamic factual reasoning capabilities.
Method: We propose an iterative adversarial generation framework guided by Retrieval-Augmented Generation (RAG) feedback: GPT-4o rewrites real news across multiple rounds, while retrieval-augmented fact verification and ROC-AUC–driven adversarial optimization jointly generate highly deceptive fake news that evades mainstream LLM-based detectors. Crucially, RAG is employed *bidirectionally*—both for detection and for adversarial generation—establishing a closed-loop system centered on real-time factual reasoning.
Contribution/Results: This is the first work to unify RAG in both detection and generation for systematic robustness evaluation. Experiments show our method reduces the ROC-AUC of strong RAG-based detectors by 17.5 percentage points, exposing critical vulnerabilities of purely generative detectors under unseen events and adversarial attacks. Our framework establishes a new benchmark and analytical paradigm for robust fake news identification.
📝 Abstract
We show that existing evaluations for fake news detection based on conventional sources, such as claims on fact-checking websites, result in high accuracies over time for LLM-based detectors -- even after their knowledge cutoffs. This suggests that recent popular fake news from such sources can be easily detected due to pre-training and retrieval corpus contamination or increasingly salient shallow patterns. Instead, we argue that a proper fake news detection dataset should test a model's ability to reason factually about the current world by retrieving and reading related evidence. To this end, we develop a novel pipeline that leverages natural language feedback from a RAG-based detector to iteratively modify real-time news into deceptive fake news that challenges LLMs. Our iterative rewrite decreases the binary classification ROC-AUC by an absolute 17.5 percent for a strong RAG-based GPT-4o detector. Our experiments reveal the important role of RAG in both detecting and generating fake news, as retrieval-free LLM detectors are vulnerable to unseen events and adversarial attacks, while feedback from RAG detection helps discover more deceitful patterns in fake news.