Role of duration and interval in perception of force pulses

Three experiments investigated the perceptual threshold for a pulsed force stimulation of the middle phalanx of the forefinger. The first experiment (N = 5) manipulated duration of the pulse, and the second (N = 6) manipulated the interval between pulses. Both experiments held magnitude constant. The results confirmed high reliability and indicated that perceptual threshold decreased as both Duration and Interval increased. Although subjects responded consistently, they described the sensation as "muscular" and "diffuse." Exp. 3 (N = 12) covaried Duration and Interval and found effects similar to those of the first two studies. Also, Duration and Interval were independent. Additional research is needed to clarify the relations of duration, interval, and magnitude in contributing to conscious perception of the presence of applied force. Treating pulse magnitude as a dynamic variable by varying its rate of change within a train of force pulses could further our understanding of how perception of force changes depend upon rate.