Hierarchical knowledge influences stimulus-response compatibility effects

The influence of spatial stimulus grouping on stimulus-response compatibility effects was investigated in three experiments. Stimuli were grouped as part of a superordinate unit BY (1) perceptually organizing them (Experiment 1), (2) organizing them on the basis of semantic links (Experiment 2), or (3) arbitrary links (Experiment 3). In some instances the arrangement of the stimuli resulted in a conflict between two types of spatial relationship: one between stimulus and response and the other between superordinate unit and response. The experiments indicated that it was the latter relationship that mainly determined performance in the experiments. Reaction time analyses showed that responses were fastest if they spatially corresponded to the relative location of the superordinate unit of which the stimulus was part. The results are discussed with reference to hierarchical accounts of coding stimulus information.