Varying the scope of attention alters the encoding of categorical and coordinate spatial relations

Two types of representations can be used to specify spatial relations: Coordinate spatial relations representations specify the precise distance between two objects, whereas categorical spatial relations representations assign a category (such as above or below) to specify a spatial relation between two objects. Computer simulation models suggest that coordinate spatial relations representations should be easier to encode if one attends to a relatively large region of space, whereas categorical spatial relations should be easier to encode if one attends to a relatively small region of space. We tested these predictions. To vary the scope of attention, we asked participants to focus on the local or global level of Navon letters, and immediately afterwards had them decide whether a dot was within 2.54 cm of a bar (coordinate judgment) or was above or below the bar (categorical judgment). Participants were faster in the coordinate task after they had just focused on the global level of a Navon letter whereas they were faster in the categorical task after they had just focused on the local level. Although we did not test the hemispheric lateralization of these effects, these findings have direct implications for theories of why the cerebral hemispheres differ in their relative ease of encoding the two kinds of spatial relations. (C) 2010 Elsevier Ltd. All rights reserved.