Performance is better when a stimulus and an assigned response spatially correspond than when they do not. In this paper, we focus on the commonality and differences between horizontal and vertical spatial representations underlying this spatial stimulus-response compatibility effect. When investigated separately, the vertical compatibility effect is comparable in size to the horizontal compatibility effect. On the other hand, their time courses differ. Moreover, the compatibility effect is

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... n larger for the horizontal dimension than for the vertical dimension when stimuli and responses simultaneously vary along both dimensions. The findings concerning these phenomena, however, indicate that there would be no intrinsic differences between horizontal and vertical spatial representations, although use of right and left effectors would affect spatial coding. In the next section we discuss cognitive correspondence between horizontal and vertical spatial representations in terms of the compatibility effect obtained with orthogonally arrayed stimuli and responses. In the last section, the implications of the findings for representation of body and space and for the automaticity in the dual-route model of the spatial compatibility effect are discussed.