Zero-Shot Multimodal Fact-Checking with Conceptual Reasoning

In multimodal fact-checking, advanced large multimodal models (LMMs) struggle to capture and integrate the complex relationships between text and images. A potential solution is to generate reasoning support text to optimize reasoning and integrate evidence. However, existing generation approaches rely heavily on high-quality data annotations for training, which are costly and limited in scalability, hindering responsiveness to evolving misinformation. To address these issues, we propose CoReS, a novel zero-shot multimodal fact-checking model based on Conceptual Reasoning Support-leveraging key concepts from evidence to guide the reasoning process and improve decision-making. This model includes a reasoning support text generation module that extracts key concepts (critical elements that significantly impact the judgment outcome) from raw textual evidence via retrieval and filtering. By using a Conceptual Reasoning LM, CoReS generates reasoning support texts framed around core key concepts that are semantically consistent with multimodal evidence, linking key clues, thus replacing redundant and complex evidence for fact-checking. The reasoning support texts generated by CoReS effectively distill complex evidence relationships and integrate important reasoning information, allowing the judgment model to provide clear and accurate judgments. Evaluations on benchmark datasets and the new multi-domain MultiVerify dataset demonstrate that CoReS excels in accuracy, generalization, and scalability.