Who Brings the Frisbee: Probing Hidden Hallucination Factors in Large Vision-Language Model via Causality Analysis

Po-Hsuan Huang, Jeng-Lin Li, Chin-Po Chen, Ming-Ching Chang, Wei-Chao Chen; Proceedings of the Winter Conference on Applications of Computer Vision (WACV), 2025, pp. 6125-6135

Recent advancements in large vision-language models (LVLM) have significantly enhanced their ability to comprehend visual inputs alongside natural language. However a major challenge in their real-world application is hallucination where LVLMs generate non-existent visual elements eroding user trust. The underlying mechanism driving this multimodal hallucination is poorly understood. Minimal research has illuminated whether contexts such as sky tree or grass field involve the LVLM in hallucinating a frisbee. We hypothesize that hidden factors such as objects contexts and semantic foreground-background structures induce hallucination. This study proposes a novel causal approach: a hallucination probing system to identify these hidden factors. By analyzing the causality between images text prompts and network saliency we systematically explore interventions to block these factors. Our experimental findings show that a straightforward technique based on our analysis can significantly reduce hallucinations. Additionally our analyses indicate the potential to edit network internals to minimize hallucinated outputs.