MIMO-Bench asked vision-language models to find one object among similar distractors, and frontier models fell well below their usual scores across 3,802 question pairs
AspireAI community · arXiv
Most multimodal benchmarks ask about object categories with few instances in frame, which lets a model reference the target trivially and hides real visual ambiguity. MIMO-Bench instead asks about instances of categories that appear many times, so the referring expression has to combine several visual subtasks to single out one object, covering attribute binding and numerical counting across 3,802 image-question pairs. Despite strong results on existing benchmarks, the authors report substantially lower performance on MIMO-Bench from both state-of-the-art open-source models (InternVL, QwenVL) and proprietary ones (Gemini, GPT-5). The benchmark is stated to be publicly available, and the images are constructed rather than collected from the wild, which keeps distractors controlled but narrows how far the finding generalizes.
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