Hierarchical coding in the perception and memory of spatial layouts

Two experiments were performed to investigate the organization of spatial i nformation in perception and memory. Participants were confronted with map- like configurations of objects which were grouped by color (Experiment 1) o r shape (Experiment 2) so as to induce cognitive clustering. Two tasks were administered: speeded verification of spatial relations between objects an d unspeeded estimation of the Euclidean distance between object pairs. In b oth experiments, verification times, but not distance estimations, were aff ected by group membership. Spatial relations of objects belonging to the sa me color or shape group were verified faster than those of objects from dif ferent groups, even if the spatial distance was identical. These results di d not depend on whether judgments were based on perceptually available or m emorized information, suggesting that perceptual, not memory processes were responsible for the formation of cognitive clusters.