The Limits of Learning from Pictures and Text: Vision-Language Models and Embodied Scene Understanding

TL;DR

This study evaluates vision-language models' ability to understand high-level scene concepts, revealing they excel in general knowledge but lack embodied understanding of affordances, highlighting the limits of distributional learning.

Contribution

The paper demonstrates that current VLMs struggle with affordance understanding and introduces a Human-Calibrated Cosine Distance metric for evaluation.

Findings

VLMs perform well on general knowledge tasks but poorly on affordance tasks.

The affordance gap is structural and not improved by newer models or explicit spatial info.

Image caption datasets lack sufficient agent-centered affordance language.

Abstract

What information is sufficient to learn the full richness of human scene understanding? The distributional hypothesis holds that the statistical co-occurrence of language and images captures the conceptual knowledge underlying visual cognition. Vision-language models (VLMs) are trained on massive paired text-image corpora but lack embodied experience, making them an ideal test of the distributional hypothesis. We report two experiments comparing descriptions generated by 18 VLMs to those of over 2000 human observers across 15 high-level scene understanding tasks, spanning general knowledge, affordances, sensory experiences, affective responses, and future prediction. Because many tasks lack ground truth answers, we developed a Human-Calibrated Cosine Distance (HCD) metric that measures VLM output similarity to the distribution of human responses, scaled by within-human variability. In Experiment 1, VLMs approached human-level performance on general knowledge tasks, but showed a robust deficit for affordance tasks that resisted prompt engineering and did not improve with newer model releases. In Experiment 2, we tested six mechanistic hypotheses for explaining this affordance gap, finding that the deficit was structural rather than stylistic and was not resolved by providing explicit spatial information. Corpus analyses revealed that image captioning datasets contain sparse agent-addressed affordance language, consistent with Gricean accounts of why embodied knowledge may be systematically underrepresented in language. Together, these findings suggest that distributional learning from images and text is insufficient for affordance-based scene understanding, implying that some dimensions of human visual cognition may require the kind of agent-centered, three-dimensional experience that no photograph or caption can encode.