Kidd G, Mason C R, Hanna T E
Department of Communication Disorders, Boston University, Massachusetts 02215.
J Acoust Soc Am. 1988 Jul;84(1):144-9. doi: 10.1121/1.396980.
The ability of experienced observers to discriminate changes in the shapes of complex sound spectra was studied for three conditions. In one condition, the reference spectrum or "background" was fixed in spectral shape across each block of trials; in a second condition, the reference spectrum differed in spectral shape from trial to trial within each block of trials but was the same for the two presentations within a trial; and, in a third condition, the reference spectrum differed in spectral shape on every stimulus presentation. The variation in the reference spectrum was a random perturbation in the amplitudes of the tonal components comprising the complex sounds. The signal was an intensity increment to the center component (1000 Hz) of the complex and was present in one interval of each two-interval, two-alternative, forced-choice trial. The principal experimental manipulations were the degree of amplitude perturbation of the reference spectrum and the interval of time between the two stimulus presentations of each trial (interstimulus interval, ISI). The theory proposed by Durlach and Braida [J. Acoust. Soc. Am. 46, 372-383 (1969)] describing memory processes involved in the perception of sound intensity was used to explain the experimental results. As that theory was applied in this study, only the condition in which the stimuli were perturbed between trials showed evidence for comparisons based on "sensory traces," while the conditions in which the stimuli were fixed or were perturbed within trials were best explained by comparisons based on judgments relative to the stimulus context.
针对三种情况，研究了经验丰富的观察者辨别复杂声谱形状变化的能力。在一种情况下，参考频谱或“背景”在每个试验块中的频谱形状是固定的；在第二种情况下，参考频谱在每个试验块内的每次试验中频谱形状都不同，但在一次试验中的两次呈现是相同的；并且，在第三种情况下，参考频谱在每次刺激呈现时频谱形状都不同。参考频谱的变化是对构成复杂声音的音调成分幅度的随机扰动。信号是对复杂声音中心成分（1000赫兹）的强度增加，并且在每个两间隔、二择一、强制选择试验的一个间隔中出现。主要的实验操作是参考频谱的幅度扰动程度以及每次试验的两次刺激呈现之间的时间间隔（刺激间隔，ISI）。Durlach和Braida [《美国声学学会杂志》46, 372 - 383 (1969)]提出的描述声音强度感知中涉及的记忆过程的理论被用于解释实验结果。当该理论应用于本研究时，只有在试验之间刺激受到扰动的情况下才显示出基于“感觉痕迹”进行比较的证据，而刺激固定或在试验内受到扰动的情况最好通过基于相对于刺激背景的判断进行比较来解释。
