MM-StanceDet: Retrieval-Augmented Multi-modal Multi-agent Stance Detection Multimodal Stance Detection (MSD) is the task of determining whether a person supports, opposes, or is neutral toward a specific target based on a combination of text and images. While this is essential for understanding public discourse on social media and news platforms, it is notoriously difficult because text and images can provide conflicting information, and models often struggle to interpret these nuances correctly. MM-StanceDet is a new framework designed to solve these issues by using a collaborative team of specialized AI agents that debate and reflect on the evidence before reaching a final conclusion. A Multi-Agent Approach to Reasoning Rather than relying on a single, fragile pass of reasoning, MM-StanceDet breaks the problem down into four distinct, collaborative stages. First, the system uses "Retrieval Augmentation" to look up similar past examples from a database, providing the model with concrete context. Second, specialized agents are assigned to analyze the text, the image, and the potential conflicts between them. Third, a "Reasoning-Enhanced Debate" stage occurs, where three separate agents—each representing a different stance (support, oppose, or neutral)—construct arguments based on the initial analysis. Finally, an "Adjudicator" agent reviews these arguments, performs a critical self-reflection to identify potential biases or errors, and determines the final stance. Why This Method Works The framework addresses three major weaknesses in current AI models: the lack of contextual grounding, the difficulty of resolving conflicting signals between images and text, and the tendency for models to make mistakes when forced to provide an answer in a single step. By forcing the system to explicitly argue for different perspectives and then reflect on those arguments, the framework creates a more transparent and robust decision-making process. This structured approach ensures that the model does not simply rely on superficial cues but instead weighs evidence from multiple angles. Performance and Results The researchers tested MM-StanceDet across five widely used datasets covering diverse topics, such as political elections, social issues, and international conflicts. The results show that the framework significantly outperforms existing state-of-the-art models. By integrating retrieval-based context with a multi-agent debate, the system demonstrates a superior ability to handle complex, nuanced, and contradictory multimodal inputs, proving that a collaborative, multi-stage architecture is more effective than traditional, single-pass methods for stance detection.