Problem Statement
For roughly a decade, vision-language models have been declared to be approaching or matching human performance on scene description (captioning). The evidence for that claim has almost always come from the same family of benchmarks—most famously MS-COCO. Those images are typically clean, well-lit, and depict either no people or people performing simple, isolated actions (sitting, walking, holding an object). They rarely require the model to parse multi-agent social dynamics, subtle intentions, or the kind of relational reasoning humans perform effortlessly when watching a movie scene or a street interaction.
Because the evaluation data are easy, the reported numbers look excellent. Automatic metrics such as BLEU-4, CIDEr, or even embedding-based scores like BERTScore further inflate the impression of progress: they reward surface lexical overlap more than genuine semantic fidelity. At the same time, almost no work has systematically catalogued which visual-cognitive failures models still commit, or how those failure modes have changed as architectures moved from CNN+LSTM captioners to today’s multimodal large language models (MLLMs). The result is a field that can claim “human-level performance” while remaining largely blind to whether the models actually understand the scenes that matter most in real applications—scenes full of people interacting.
