| An experiment tested three alternative theories of the mental representation of spatial knowledge: Nonhierarchical, hierarchical, and partially-hierarchical theories. According to nonhierarchical theories, spatial knowledge is mentally represented in a simple network or in an image-like, analog format. Under hierarchical theories, different regions of an environment are represented in different sections of the mental representation. These sections are proposed to be organized in a strict hierarchy. Finally, partially-hierarchical theories propose that spatial knowledge is mentally represented in a partial hierarchy, such that spatial relations between certain locations in different regions of an environment--and consequently, in different sections of the mental representation--are explicitly represented. These connections violate a strictly hierarchical representation. These theories were tested by having subjects learn the locations of actual objects in spatial layouts or the locations of objects on maps of these layouts. These layouts and maps were divided into regions with transparent boundaries (the layouts) or lines (the maps). After learning the layouts or maps subjects participated in three tasks: recognition of object names, direction judgments, and Euclidean distance estimation. Results from all three tasks were sensitive (a) to the Euclidean distance between objects and (b) to whether objects were in the same region or in different regions. These findings were interpreted as supporting partially-hierarchical theories of spatial representation. |
