Abstract
The vibration problems related to living bodies have so far been studied from the perspectives of engineering, physiology, and psychology. This study shows the relationship between vibratory sensibility and temperature in the living body. Psychological experiments were carried out by using the vibrometer of an acoustical calibration apparatus in sine, triangular and square waves. The sensibility-threshold measurements were made using 30-700 Hz sine waves, 30-300Hz triangular and sawtooth waves, or 30-250Hz square waves. Each of ten subjects was kept seated. The average value of the vibratory levels, varied by ascending and descending steps, was taken as that of the threshold. As the vibrometer in the apparatus used makes a noise at frequencies greater than 250 Hz, it was masked from the subject by presenting him with a different noise. The threshold curve for square waves was lower by 12.3 dB than that for sine waves at about 30Hz. The threshold curve of the 26℃ sine wave was lower by 10 dB than that of the 58℃ sine wave vibration near 200 Hz. At frequency stimulation higher than 120 Hz, as the temperature of the contact point was lowered, the amplitude threshold increased and the frequency at which the threshold curve was at a minimum shifted to a lower frequency. In addition, a model of the vibratory sensibility system was constructed by electronic circuits. Its spatio-temporal characteristics were compared with the neurophysiological and psychological data on human vibratory sensibility. The results showed qualitative agreement with the fundamental neurophysiological and psychological data.
