Seeing to Generalize: How Visual Data Corrects Binding Shortcuts
Organizations: Department of Computer Science, Pontificia Universidad Católica, Santiago, Chile · 2Centro Nacional de Inteligencia Artificial (CENIA), Santiago, Chile · 3Instituto Milenio en Ingeniería e Inteligencia Artificial para la Salud (iHEALTH), Santiago, Chile.
Abstract
Vision Language Models (VLMs) are designed to extend Large Language Models (LLMs) with visual capabilities, yet in this work we observe a surprising phenomenon: VLMs can outperform their underlying LLMs on purely text-only tasks, particularly in long-context information retrieval. To investigate this effect, we build a controlled synthetic retrieval task and find that a transformer trained only on text achieves perfect in-distribution accuracy but fails to generalize out of distribution, while subsequent training on an image-tokenized version of the same task nearly doubles text-only OOD performance. Mechanistic interpretability reveals that visual training changes the model's internal binding strategy: text-only training encourages positional shortcuts, whereas image-based training disrupts them through spatial translation invariance, forcing the model to adopt a more robust symbolic binding mechanism that persists even after text-only examples are reintroduced. We further characterize how binding strategies vary across training regimes, visual encoders, and initializations, and show that analogous shifts occur during pretrained LLM-to-VLM transitions. Our findings suggest that cross-modal training can enhance reasoning and generalization even for tasks grounded in a single modality.
Figures & tables
| Model | Peak Layer | Sym./Pos. Ratio | |
|---|---|---|---|
| Qwen 2 | 22 | 1.383 | — |
| Qwen 2-VL | 22 | 1.499 | +0.116 |
| Qwen 2.5 | 22 | 1.218 | — |
| Qwen 2.5-VL | 22 | 1.282 | +0.064 |
| Qwen 3 | 28 | 1.819 | — |
| Qwen 3-VL | 28 | 2.463 | +0.644 |
Appendix figures & tables11 assets
Supplementary material from the paper’s appendix.
Appendix
| Hyperparameter | Value |
|---|---|
| Number of layers | 12 |
| Hidden dimension ( ) | 128 |
| FFN dimension ( ) | 512 |
| Attention heads | 4 |
| Positional encoding | RoPE ( ) |
| Dropout | 0 |
Cross-Modal Learning
Cross-modal learning connects information across different data types, enabling models to align, transfer, and reason across modalities.
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