
Vision-language models show hidden brittleness to prompt order
Vision-language models exhibit a systematic brittleness: they perform measurably better when images precede text prompts rather than the reverse, despite this ordering being semantically irrelevant. Researchers identified this modality-order failure across multiple architectures and datasets, then developed a test-time training approach that not only closes the performance gap but also improves the stronger branch, creating mutual consistency gains. Activation patching revealed the failure concentrates in mid-network layers where representations diverge sharply by prompt order. This work exposes a fundamental robustness vulnerability in multimodal systems and demonstrates that targeted intervention at inference time can recover hidden model capacity.62




























