Perceiving topological relations

There are many ways to describe and represent the visuospatial world. A space can be described by its Euclidean properties: the size of objects, the angles of boundaries, the distances between them. A space can also be described in non-spatial terms: One could explain the layout of a city by the order of its streets. Somewhere in between, topological representations — such as those commonly depicted in public transit maps — capture coarse relational structure without precise Euclidean detail, offering a relatively efficient, low-dimensional way of capturing spatial content. Here, we ask whether people quickly and automatically perceive such relations. In six experiments, we show that differences in simple topological features influence a range of visual tasks from object matching to number estimation to visual search. We discuss the possibility that topological relations are a kind of visual primitive that supports visuospatial representation.