A possible connection between categorical and coordinate spatial relation representations.

Kosslyn (1987) theorized that the visual system uses two types of spatial relations. Categorical spatial relations represent a range of locations as an equivalence class, whereas coordinate spatial relations represent the precise distance between two objects. Data indicate a left hemisphere (LH) advantage for processing categorical spatial relations and a right hemisphere (RH) advantage for processing coordinate spatial relations. Although generally assumed to be independent processes, this article proposes a possible connection between categorical and coordinate spatial relations. Specifically, categorical spatial relations may be an initial stage in the formation of coordinate spatial relations. Three experiments tested the hypothesis that categorical information would benefit tasks that required coordinate judgments. Experiments 1 and 2 presented categorical information before participants made coordinate judgments and coordinate information before participants made categorical judgments. Categorical information sped the processing of a coordinate task under a range of experimental variables; however, coordinate information did not benefit categorical judgments. Experiment 3 used this priming paradigm to present stimuli in the left or right visual field. Although visual field differences were present in the third experiment, categorical information did not speed the processing of a coordinate task. The lack of priming effects in Experiment 3 may have been due to methodological changes. In general, support is provided that categorical spatial relations may act as an initial step in the formation of more precise distance representations, i.e., coordinate spatial relations.