Spatial Colour Mixing Illusions as a Perception Stress Test for Vision-Language Models
On the map: Multimodal LLMs / vision-language models → VLM benchmarks and visual reasoning
Abstract (arXiv)
Vision-language models (VLMs) achieve strong benchmark results, yet can exhibit systematic perceptual weaknesses: structured, large changes to pixel values can cause confident yet nonsensical predictions, even when the underlying scene remains easily recognizable to humans. We study this gap using Spatial Colour Mixing, a programmatic family of colour distortions that overlays structured patterns (in both RGB and Ostwald colour systems) onto natural images. We introduce a framework of eight spatial colour mixing variants and evaluate nine VLMs across three model families on four datasets. Across models and datasets, accuracy degrades sharply with increasing distortion, and scaling the language model does not reliably mitigate the failure. In a human study with 61 participants on an animal recognition dataset, humans substantially outperform VLMs under the same distortions. Finally, we show that a simple human-inspired preprocessing step recovers a meaningful portion of performance for several distortion types, motivating perception-aware preprocessing and tool-use as practical strategies for improving VLM robustness.
Key facts. No citing papers in the map yet (data through 7 Oct 2026). Placed in VLM benchmarks and visual reasoning, one of 16 directions in Multimodal LLMs / vision-language models. Builds on 25 of its 54 references that are in the map. First posted on arXiv 6 Mar 2026.
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25 of 54 references.
Closest ancestors · 8
Same direction, newest first
- 2025Vision Language Models are Biased29 May
- 2025A Survey of State of the Art Large Vision Language Models: Alignment, Benchmark, Evaluations and Challenges4 Jan
- 2025IllusionBench+: A Large-scale and Comprehensive Benchmark for Visual Illusion Understanding in Vision-Language Models1 Jan
- 2024Evaluating Model Perception of Color Illusions in Photorealistic Scenes9 Dec
- 2024An Introduction to Vision-Language Modeling27 May
- 2023PaLI-3 Vision Language Models: Smaller, Faster, Stronger13 Oct
- 2023MathVista: Evaluating Mathematical Reasoning of Foundation Models in Visual Contexts3 Oct
- 2022A Survey of Vision-Language Pre-Trained Models18 Feb
Other references · 17
- 2021Learning Transferable Visual Models From Natural Language Supervisioncited by 33,456
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- 2025DINOv3cited by 1,297
- 2025SigLIP 2: Multilingual Vision-Language Encoders with Improved Semantic Understanding, Localization, and Dense Featurescited by 1,127
- 2023SEED-Bench: Benchmarking Multimodal LLMs with Generative Comprehensioncited by 929
- 2024BLINK: Multimodal Large Language Models Can See but Not Perceivecited by 529
5 more
- 2020Google Landmarks Dataset v2 -- A Large-Scale Benchmark for Instance-Level Recognition and Retrievalcited by 305
- 2023PaLI-X: On Scaling up a Multilingual Vision and Language Modelcited by 254
- 2025VTool-R1: VLMs Learn to Think with Images via Reinforcement Learning on Multimodal Tool Usecited by 84
- 2024Illusory VQA: Benchmarking and Enhancing Multimodal Models on Visual Illusionscited by 10
- 2024Vision-Language Models Align with Human Neural Representations in Concept Processingcited by 2
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- 2026Seeing Is Believing? A Benchmark for Multimodal Large Language Models on Visual Illusions and Anomalies
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- 2026Seeing Red, Thinking Bad: Color Bias in Vision Language Models
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