Abstract
When we open our eyes, we immediately see the colors, shapes, and sizes of the objects around us — round apples, wooden tables, small kittens, and so on — all without effort or intention. Now consider relations between these objects: An apple supported by a table, or two kittens chasing one another. Are these experiences just as immediate and perceptual, or do they require effort and reflection to arise? Which properties of relations are genuinely perceived, and how can we know? Here, we outline a framework for distinguishing perception of relations from mere judgments about them, centered on behavioral "signatures" that implicate rapid, automatic visual processing as distinct from high-level judgment. We then discuss several case studies demonstrating that visual relations fall within this framework. First, we show that physical relations such as containment and support are extracted in an abstract manner, such that instances of these relations involving very different objects are confused for one another in fast target-identification tasks. Second, we show that the mind "fills in" required elements of a relation that are inferred from physical interaction (e.g., a man running into an invisible "wall"), producing visual priming in object detection tasks. Third, we show that when objects look like they can physically fit together, this impression influences numerosity estimates of those objects. We argue that visual processing itself extracts sophisticated, structured relations, and we reflect on the consequences of this view for theorizing about visual perception more broadly.