Stimulus-response compatibility as a function of stimulus code and response modality

The concept of stimulus-response compatibility can be differentiated into set-level and element-level compatibility. The relation between these 2 types of compatibility was examined by varying stimulus code (spatial or verbal) and response modality (manual or vocal) in 2-choice tasks that used left-right stimuli and left-right responses. Element-level compatibility was an increasing function of set-level compatibility and larger for verbal than for spatial stimuli. The positive relation between set- and element-level compatibility was due to differences for the congruent mapping but not the incongruent mapping. The results can be characterized in terms of (a) a continuum along which the relative compatibility of the responses with spatial and verbal stimuli varies and (b) a dual-route conception of response selection in which a direct, or automatic, route is involved only when a congruent mapping is in effect.