Vibrotactile thresholds measured at the finger

Absolute vibrotactile thresholds were determined over the distal pad of the middle finger and thenar eminence of the right hands of five Ss. Measurements were made using eight frequencies between 25 and 700 Hz and seven contactor sizes between .0008 and 1.3 cm². When plotted as a function of frequency, the threshold curve measured at the fingerpad with a .005-cm² contactor is U shaped, with a maximum sensitivity in the region of 250 Hz. When plotted as a function of contactor size, the threshold decreases at a rate of 3 dB per doubling of the area.