Echo suppression and discrimination suppression aspects of the precedence effect
Echo suppression and discrimination suppression aspects of the precedence effect
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DOI：
10.3758/bf03205525
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发表时间：
1997-10-01
期刊：
影响因子：
--
通讯作者：
Grantham, DW
中科院分区：
文献类型：
--
作者：
Yang, XF;Grantham, DW
优先效应是一种现象，当来自一个方向（领先）的声音在几毫秒内被来自另一个方向（滞后或回声）的相同或相似的声音跟随时，可能会发生这种现象。典型地，滞后声音不作为单独的事件被听到，并且滞后声音的方向的改变不能被辨别。在这项研究中提出的假设，这两个方面的优先（回声抑制和歧视抑制）是至少部分独立的现象。进行了两个实验，其中对噪声突发呈现给受试者从两个扬声器在水平面上，以模拟铅的声音和滞后的声音（回声）。回声抑制阈值被测量为受试者报告听到两种声音而不是一种声音的最小回声延迟;辨别抑制阈值被测量为受试者可以可靠地区分回声的两个位置的最小回声延迟。在实验1中，发现当用单个脉冲串对测量时，回波抑制阈值与辨别抑制阈值相同（平均5.4msec）。然而，当在呈现一系列脉冲串对（可能产生“抑制积聚”的条件）之后进行测量时，辨别抑制阈值增加到10.4毫秒，而回声抑制阈值增加到26.4毫秒。回波抑制比鉴别抑制的建立更大，表明这两种现象在建立条件下是不同的，并且可能是不同的潜在机制的反映。实验2研究了超前声和滞后声的方向性对辨别抑制和回声抑制的影响。导联和滞后源之间的空间分离对辨别抑制或回声抑制没有一致的影响，两种类型的阈值之间也没有任何一致的差异（总体平均阈值为5.9 msec）。实验2中的负结果可能是由于仅针对单刺激条件而不是针对可能涉及听觉系统的更多中央处理的累积条件获得测量结果。
The precedence effect is a phenomenon that may occur when a sound from one direction (the lead) is followed within a few milliseconds by the same or a similar sound from another direction (the lag, or the echo). Typically, the lag sound is not heard as a separate event, and changes in the lag sound's direction cannot be discriminated. The hypothesis is proposed in this study that these two aspects of precedence (echo suppression and discrimination suppression) are at Least partially independent phenomena. Two experiments were conducted in which pairs of noise bursts were presented to subjects from two loudspeakers in the horizontal plane to simulate a lead sound and a lag sound (the echo). Echo suppression threshold was measured as the minimum echo delay at which subjects reported hearing two sounds rather than one sound; discrimination suppression threshold was measured as the minimum echo delay at which subjects could reliably discriminate between two positions of the echo. In Experiment 1, it was found that echo suppression threshold was the same as discrimination suppression threshold when measured with a single burst pair (average 5.4 msec). However, when measured after presentation of a train of burst pairs (a condition that may produce ''buildup of suppression''), discrimination suppression threshold increased to 10.4 msec, while echo suppression threshold increased to 26.4 msec. The greater buildup of echo suppression than of discrimination suppression indicates that the two phenomena are distinct under buildup conditions and may be the reflection of different underlying mechanisms. Experiment 2 investigated the effect of the directional properties of the lead and lag sounds on discrimination suppression and echo suppression. There was no consistent effect of the spatial separation between lead aid lag sources on discrimination suppression or echo suppression, nor was there any consistent difference between the two types of thresholds (overall average threshold was 5.9 msec). The negative result in Experiment 2 may have been due to the measurements being obtained only for single-stimulus conditions and not for buildup conditions that may involve more central processing by the auditory system.