Figure 3

<p> <b>Top</b>: Illustration of the design of Experiment 3, in which two vibrations were either presented on the same index finger (both left or both right) or were presented on opposite index fingers. <b>Below</b>: Results for same-finger and opposite-finger comparisons of vibrations that either had matched amplitude (and thus differing velocity) or had matched velocities (vertical bars represent within-subject SEM). The subjects' ability to discriminate the frequency of the two vibrations decreased (their discrimination threshold increased) if the vibrations had matched velocity, or if the vibrations were presented to opposite fingers, and these two effects were additive in that the subjects performed worst when comparing matched-velocity vibrations presented on opposite fingers.