Qualitative differences in the representation of spatial relations for different object classes.

Two experiments investigated whether the representations used for animal, produce, and object recognition code spatial relations in a similar manner. Experiment 1 tested the effects of planar rotation on the recognition of animals and nonanimal objects. Response times for recognizing animals followed an inverted U-shaped function, whereas those for basic-level object recognition followed an M-shaped function (with a dip at 1800). Experiment 2 tested for laterality effects in the recognition of animals, produce, and objects. A right-hemisphere advantage was found for recognizing animals, whereas no hemispheric advantages were found for recognizing produce or objects. These results suggest that the recognition of animals with nonunique structural descriptions is mediated using coordinate spatial relations, whereas most forms of basic-level object recognition are mediated using categorical spatial relations.