A 2-interval forced choice design will be used with the usual timing
interval 1 (1-second) interval 2 (1-second) response period
The subject's task will be to detect which interval contains a tactile buzz, and press a mouse button labelled "1" or "2" corresponding to the interval.
A 200 Hz tactile buzz will be used, placed in the central 500-ms of one of the intervals. Before the experiment, the intensity of the buzz will be adjusted so that it is detectable about 70% of the time.
Some trials will also have an auditory stimulus. For auditory trials, both intervals will contains the same auditory stimulus.
There will be five auditory stimuli and therefore six total trial types (no auditory + 5 auditory stimuli).
The auditory stimulus will be either a 200 Hz tone, or two tones on either side of 200 Hz.
perhaps 100 Hz, 150 Hz, 250 Hz, 300 Hz; spaced as octaves or a set fraction thereof.
There will be 60 presentations of each trial type.
The prediction is that performance will be best for the congruent 200 Hz tone and worst for the no sound trials.
There will be a U-shaped accuracy function with incongruent sounds resulting in progressively worse performance as the frequency difference between the sound and the touch increases.