Gescheider G A, Bolanowski S J, Verrillo R T, Arpajian D J, Ryan T F
Hamilton College, Clinton, New York 13323.
J Acoust Soc Am. 1990 Jan;87(1):330-8. doi: 10.1121/1.399300.
The difference threshold for the detection of changes in vibration amplitude was measured as a function of the intensity and frequency of stimuli delivered through a 2.9-cm2 contactor to the thenar eminence. Stimuli were either 25- or 250-Hz sinusoids, narrow-band noise centered at 250 Hz, or wideband noise. Thresholds were measured by two-interval, forced-choice tracking under three methods of stimulus presentation. In the gated-pedestal method, subjects had to judge which of two 700-ms bursts of vibration separated by 100 ms was more intense. In the continuous-pedestal method, subjects had to detect a 700-ms increment in the amplitude of an ongoing pedestal of vibration. In the two-burst-continuous-pedestal method with 1500-ms pedestals, the subject had to detect which of two successively presented pedestals contained a 500-ms amplitude increment. Thresholds were consistently lower for detecting increments in the amplitude of a continuous pedestal of vibration than for detecting amplitude differences between briefly presented successive pedestals or amplitude increments in successive pedestals. A "near miss" to Weber's law was found both for sinusoidal and for noise stimuli. The difference threshold was not affected by stimulus frequency condition.
通过一个2.9平方厘米的接触器向鱼际隆起施加刺激，测量检测振动幅度变化的差异阈值，该阈值是刺激强度和频率的函数。刺激包括25赫兹或250赫兹的正弦波、以250赫兹为中心的窄带噪声或宽带噪声。在三种刺激呈现方法下，通过双间隔、强制选择跟踪来测量阈值。在门控基座法中，受试者必须判断两个间隔100毫秒、持续700毫秒的振动脉冲中哪个更强。在连续基座法中，受试者必须检测正在进行的振动基座幅度增加700毫秒的情况。在具有1500毫秒基座的双脉冲连续基座法中，受试者必须检测两个连续呈现的基座中哪个包含500毫秒的幅度增量。检测连续振动基座幅度的增量时的阈值始终低于检测短暂呈现的连续基座之间的幅度差异或连续基座中的幅度增量时的阈值。对于正弦波和噪声刺激，都发现了接近韦伯定律的情况。差异阈值不受刺激频率条件的影响。
