Compatibility effects between sound frequency and tactile elevation

Participants made speeded discrimination responses to unimodal auditory (low-frequency vs. high-frequency sounds) or vibrotactile stimuli (presented to the index finger, upper location vs. to the thumb, lower location). In the compatible blocks of trials, the implicitly related stimuli (i.e. higher-frequency sounds and upper tactile stimuli; and the lower-frequency sounds and the lower tactile stimuli) were associated with the same response key; in the incompatible blocks, weakly related stimuli (i.e. high-frequency sounds and lower tactile stimuli; and the low-frequency sounds and the upper tactile stimuli) were associated with the same response key. Better performance was observed in the compatible (vs. incompatible) blocks, thus providing empirical support for the cross-modal association between the relative frequency of a sound and the relative elevation of a tactile stimulus.