Serial search and comparison of features of imagined and perceived objects

Four experiments studied the spatial information processing involved in making a series of same-different comparisons of features of two objects. When the path between successively compared features on one object was antiparallel with the corresponding path on the other, comparison of a series of features took longer and produced many more errors. These results were observed both when the objects were externally presented and when one object was imagined and the other externally presented. Knowing the location of the next feature seems much more important for effective search than does monitoring the location of the feature used in the preceding comparison. When paths between corresponding features are parallel, search of features of one object may guide search of the other. When the directions between corresponding features are incongruous, search for the next angle may produce a competition for processes or processing resources, or may produce interfering cross-talk between the spatial information processing of the concurrent search tasks. Because of incongruity, as demonstrated in this study, serial search of objects at different orientations is difficult.