Auditory Streaming as an Online Classification Process with Evidence Accumulation
Auditory Streaming as an Online Classification Process with Evidence Accumulation
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DOI：
10.1371/journal.pone.0144788
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发表时间：
2015-12-15
期刊：
影响因子：
3.7
通讯作者：
Nelken, Israel
中科院分区：
文献类型：
--
作者：
Barniv, Dana;Nelken, Israel
当人类受试者听到两个交替的纯音序列时，他们通常以两种方式之一感知它：作为一个完整的序列（由两个音调组成的单个“流”），或作为两个分离的序列，一个低音序列与另一个高音序列（两个“流”）分开感知。因此，对这种刺激的感知是双稳态的。此外，受试者报告了两种感知之间的持续切换：除非频率分离很大，否则最初的感知往往是整合，然后是整合和分离阶段之间的切换。流形成的过程被笼统地称为“听觉流”。听觉流被认为是人类分析听觉场景的能力的表现，即将传入声音序列的部分归因于不同的声音生成实体。先前的研究表明，连续的整合和分离阶段的持续时间在统计上是独立的。这种独立性在当前的双稳态模型中发挥着重要作用。与此相反，我们在这里通过分析大量数据表明，后续阶段持续时间是正相关的。为了共同考虑双稳态和后续持续时间之间的正相关性，我们认为流媒体是证据积累过程的结果。隔离的证据是在整合阶段积累的，反之亦然；基于这一证据，向相反感知的转变是随机发生的。在一个漫长的阶段中，积累了大量相反感知的证据，导致了一个漫长的后续阶段。相反，一个短阶段之后是另一个短阶段。我们使用概率模型来实现这些概念，该模型显示了与实验观察到的类似的双稳态和相关性。
When human subjects hear a sequence of two alternating pure tones, they often perceive it in one of two ways: as one integrated sequence (a single "stream" consisting of the two tones), or as two segregated sequences, one sequence of low tones perceived separately from another sequence of high tones (two "streams"). Perception of this stimulus is thus bistable. Moreover, subjects report on-going switching between the two percepts: unless the frequency separation is large, initial perception tends to be of integration, followed by toggling between integration and segregation phases. The process of stream formation is loosely named "auditory streaming". Auditory streaming is believed to be a manifestation of human ability to analyze an auditory scene, i.e. to attribute portions of the incoming sound sequence to distinct sound generating entities. Previous studies suggested that the durations of the successive integration and segregation phases are statistically independent. This independence plays an important role in current models of bistability. Contrary to this, we show here, by analyzing a large set of data, that subsequent phase durations are positively correlated. To account together for bistability and positive correlation between subsequent durations, we suggest that streaming is a consequence of an evidence accumulation process. Evidence for segregation is accumulated during the integration phase and vice versa; a switch to the opposite percept occurs stochastically based on this evidence. During a long phase, a large amount of evidence for the opposite percept is accumulated, resulting in a long subsequent phase. In contrast, a short phase is followed by another short phase. We implement these concepts using a probabilistic model that shows both bistability and correlations similar to those observed experimentally.