STIMULUS MODALITY AND STIMULUS-RESPONSE COMPATIBILITY IN ABSOLUTE IDENTIFICATION

Accuracy and response time (RT) were measured in the absolute identifi cation (Al) of ten unidi-mensional perfectly pairwise discriminable st imuli. One group of 20 subjects performed a visual AI task involving l ine segments of variable length. A second group of 20 subjects partici pated in an auditory task with the stimuli composed of pure tones of v ariable intensity. Subjects performed the task under two conditions: a spatially compatible and a spatially incompatible stimulus-response m apping. Results showed greater accuracy for the visual modality and lo nger RT for the incompatible mapping. The experimental factors did not substantially alter the bowing observed when performance was plotted according to the ordinal position of the stimuli. The data do not supp ort the hypothesis that the bow effect is attributable to motor progra mming or motor adjustment stages.