TACTILE-INFORMATION-PROCESSING MECHANISMS OF FINE-SURFACE-TEXTURE DISCRIMINATION
The purpose of the present study was to investigate low-pass filter characteristics and to verify the â€œamplitude-information hypothesisâ€ of fine-surface-texture discrimination in human tactile perception. Two experiments were performed. In Experiment 1, six diffraction gratings were used as stimuli. Their wavelengths were 6.7, 13.3, 25.0, 33.3, 50.0, and 75.2 Î¼m. Six subjects touched the stimuli, which were moving at three different velocities, and judged the roughness of the stimuli with the two-alternative, forced-choice technique. Psychometric functions, calculated from the experimental data, clearly showed the existence of the low-pass filter. In Experiment 2, five abrasive papers with particle sizes between 1 and 30 Î¼m were used as stimuli. The six subjects who participated in Experiment 1 also participated in Experiment 2. Patterns of psychometric functions obtained in the experiment were similar to each other despite the change in the velocities of the stimuli. The obtained results support the amplitude-information hypothesis.