The name is absent

105

alternately presented as the subject adjusted the voltage of the 200 Hz vibration to
match the perceived intensity of the 100 Hz vibration. This modified staircase procedure
(with random initial voltages for the 200 Hz vibration) was performed three times, with
the mean voltage used for the experiment.

The auditory stimulus, when delivered, was either a 100 Hz or a 200 Hz pure
frequency tone (59 dB or 60 db in intensity, respectively) delivered for 250 ms over a
speaker placed 50 cm in front of the left hand. Thus, the auditory stimulus could either
be congruent or incongruent with the tactile stimulus. The position and distance of the
speaker from the hand was such that no air pressure was felt on the hand from the
sounds. As in Experiments 1 and 2, the participants' left hands rested on the armrest of
their chair.

A3 sound (100 Hz, 200 Hz, or no sound) × 2 touch (100 Hzor 200 Hz) factorial
design was used. The start of each trial was signaled by a white fixation cross that was
presentedfor 500 ms at the center of a blank LCD monitor. The participant's performed
a 2-AFC task, reporting whether the tactile stimulus on each trial was the low (i.e. 100
Hz) or high (i.e. 200 Hz) tactile stimulus frequency, ignoring any auditory stimulation.
Each subject performed 20 trials for each of the 6 conditions for a total of 120 trials. The
data were collapsed across stimulation frequency, resulting in 40 trials for congruent
auditory and tactile stimulation, 40 trials of incongruent auditory and tactile stimulation,
and 40 trials for tactile stimulation with no auditory stimulus.

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