Regularity extraction from non-adjacent sounds
Regularity extraction from non-adjacent sounds
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DOI：
10.3389/fpsyg.2012.00143
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发表时间：
2012-01-01
影响因子：
3.8
通讯作者：
Winkler, Istvan
中科院分区：
文献类型：
--
作者：
Bendixen, Alexandra;Schroeger, Erich;Winkler, Istvan
声源的规律性行为有助于我们理解听觉环境。例如，规则图案可以传达关于声源的身份的信息(例如在轨道上移动的列车的声学特征)。然而，通常情况下，该特征在时间上与从其他声源发出的信号重叠。通常认为，听觉规则提取不能对这种混合信号进行操作，因为它只发现相邻声音之间的规则。在这一观点中，听觉环境将通过容易获得的声学提示，如频率和位置上的分离，被分成不同的实体。然后，规则性提取过程将对结果组进行操作。我们的新实验证据挑战了这一观点。我们提出了两个交织的声音序列，它们在频率范围内重叠，并且共享所有的声学参数。这些序列只是在其潜在的规律模式上有所不同。我们在其中一个序列中插入了偏差，以检测是否提取了规律性。在第一个实验中，我们发现这些偏差引起了失配负向(MMN)分量。因此，听觉系统能够发现不相邻声音之间的规律性。正则性提取不受序列衔接的影响，不受声调和静音音间间隔的相对时长的影响。在第二个实验中，我们发现只有当插入的声音序列也包含有规律的模式时，才会发现连接不相邻声音的规律，而不是当插入的声音是随机变化的时。这表明听觉系统可以利用不同的规律模式作为识别来自不同声源的信号的线索。因此，听觉规则性提取不一定限于初始声音分组之后的处理阶段，而是当其他声学提示不可用时可以在分组之前。
The regular behavior of sound sources helps us to make sense of the auditory environment. Regular patterns may, for instance, convey information on the identity of a sound source (such as the acoustic signature of a train moving on the rails). Yet typically, this signature overlaps in time with signals emitted from other sound sources. It is generally assumed that auditory regularity extraction cannot operate upon this mixture of signals because it only finds regularities between adjacent sounds. In this view, the auditory environment would be grouped into separate entities by means of readily available acoustic cues such as separation in frequency and location. Regularity extraction processes would then operate upon the resulting groups. Our new experimental evidence challenges this view. We presented two interleaved sound sequences which overlapped in frequency range and shared all acoustic parameters. The sequences only differed in their underlying regular patterns. We inserted deviants into one of the sequences to probe whether the regularity was extracted. In the first experiment, we found that these deviants elicited the mismatch negativity (MMN) component. Thus the auditory system was able to find the regularity between the non-adjacent sounds. Regularity extraction was not influenced by sequence cohesiveness as manipulated by the relative duration of tones and silent inter-tone-intervals. In the second experiment, we showed that a regularity connecting non-adjacent sounds was discovered only when the intervening sequence also contained a regular pattern, but not when the intervening sounds were randomly varying. This suggests that separate regular patterns are available to the auditory system as a cue for identifying signals coming from distinct sound sources. Thus auditory regularity extraction is not necessarily confined to a processing stage after initial sound grouping, but may precede grouping when other acoustic cues are unavailable.