Moore B C, Emmerich D S
Department of Experimental Psychology, University of Cambridge, England.
J Acoust Soc Am. 1990 Jun;87(6):2628-33. doi: 10.1121/1.399055.
This article presents the results of two experiments investigating performance on a monaural envelope correlation discrimination task. Subjects were asked to discriminate pairs of noise bands that had identical envelopes (referred to as correlated stimuli) from pairs of noise bands that had envelopes which were independent (uncorrelated stimuli). In the first experiment, a number of stimulus parameters were varied: the center frequency of the lower frequency noise band in a pair, f1; the frequency separation between component noise bands; the duration of the stimuli; and the bandwidth of the component noise bands. For a long stimulus duration (500 ms) and a relatively wide bandwidth (100 Hz), subjects could easily discriminate correlated from uncorrelated stimuli for a wide range of frequency separations between the component noise bands. This was true both when f1 was 350 Hz, and when f1 was 2500 Hz. In each case, narrowing the bandwidth to 25 Hz, or shortening the duration to 100 ms, or both, made the task more difficult, but not impossible. In the second experiment, the level of the higher frequency noise band in a pair was varied. Performance did not decrease monotonically as the level of this band was decreased below the level of the other band, and only showed marked impairment when the level of the higher frequency band was at least 60 dB below that of the lower frequency band. The pattern of results in these two experiments is different from that which is obtained when the same stimulus parameters are varied in experiments investigating comodulation masking release (CMR). This suggests that the mechanisms underlying CMR and those underlying the discrimination of envelope correlation are not identical.
本文介绍了两项关于单耳包络相关性辨别任务表现的实验结果。受试者被要求区分具有相同包络的噪声带对（称为相关刺激）和具有独立包络的噪声带对（不相关刺激）。在第一个实验中，改变了多个刺激参数：一对中低频噪声带的中心频率f1；组成噪声带之间的频率间隔；刺激的持续时间；以及组成噪声带的带宽。对于较长的刺激持续时间（500毫秒）和相对较宽的带宽（100赫兹），在组成噪声带之间的频率间隔范围较广时，受试者能够轻松区分相关刺激和不相关刺激。当f1为350赫兹时以及当f1为2500赫兹时都是如此。在每种情况下，将带宽缩小到25赫兹，或将持续时间缩短到100毫秒，或两者同时进行，都会使任务变得更困难，但并非不可能完成。在第二个实验中，改变了一对中高频噪声带的电平。当该频段的电平低于另一个频段的电平时，表现并不会单调下降，只有当高频段的电平比低频段至少低60分贝时，才会出现明显的损伤。这两项实验的结果模式与在研究共调制掩蔽释放（CMR）的实验中改变相同刺激参数时所获得的结果模式不同。这表明CMR背后的机制和包络相关性辨别背后的机制并不相同。
