The past, present, and future of relation perception

What kind of information does perception represent, and in what format? How does perception interface with higher-level cognitive systems for thinking, reasoning, and language? Questions like these motivated Green and Hummel (henceforth, G&H) in their seminal 2006 article in JEP:HPP, “Familiar Interacting Object Pairs Are Perceptually Grouped.” At first glance, the subject matter of G&H’s article appears quite simple and mundane: actions like pouring coffee, cutting bread, or unlocking a door. Yet hidden at the core of such everyday routines are specific functional relationships between objects, such as a carafe and a mug, a knife and a loaf, or a key and a lock. G&H’s article was a turning point in a long but sparse tradition of research that had considered such relations from a vision-science perspective (e.g., Scholl & Tremoulet, 2000), as it steered many researchers — ourselves included — to explore questions in the burgeoning field now known as “relation perception.” This field advances the idea that, beyond objects, features, and locations, the visual system extracts and represents relations — properties that specify interactions or connections between objects, rather than each object’s characteristics. In this perspective article, we outline new aspects of human visual perception that have been the focus of this field, and the major outstanding questions that remain.