In a sequence of otherwise equal sounds, listeners tend to hear a series of trochees (groups of two sounds with an initial beat) when every other sound is louder; they tend to hear a series of iambs (groups of two sounds with a final beat) when every other sound is longer. The article presents evidence that this so-called “Iambic–Trochaic Law” (ITL) is a consequence of the way listeners parse the signal along two orthogonal dimensions, grouping (Which tone is first/last?) and prominence (Which tone is prominent?). A production experiment shows that in speech, intensity and duration correlate when encoding prominence, but anticorrelate when encoding grouping. A model of the production data shows that the ITL emerges from the cue distribution based on a listener’s predicted decisions about prominence and grouping respectively. This, and further predictions derived from the model, are then tested in speech and tone perception. The perception results provide evidence that intensity and duration are excellent cues for grouping and prominence, but poor cues for the distinction between iamb and trochee per se. Overall, the findings illustrate how the ITL derives from the way listeners recover two orthogonal perceptual dimensions, grouping and prominence, from a single acoustic stream. (PsycInfo Database Record (c) 2021 APA, all rights reserved)

中文翻译：

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声流的二维解析解释了 Iambic-Trochaic 定律。

在其他相同的声音序列中，当其他声音都更大时，听众往往会听到一系列音节（两个声音的组，具有初始节拍）；当其他声音较长时，他们往往会听到一系列 iambs（最后一拍的两个声音组）。这篇文章提供的证据表明，这种所谓的“Iambic-Trochaic Law”（ITL）是听众沿两个正交维度解析信号的方式的结果，分组（哪个音调是第一个/最后一个？）和突出（哪个音调是突出的）？）。生产实验表明，在语音中，强度和持续时间在对突出度进行编码时相关，但在对分组进行编码时是反相关的。生产数据模型表明，ITL 是根据听众对突出和分组的预测决策分别从提示分布中产生的。然后在语音和语调感知中测试这一点以及从模型中得出的进一步预测。感知结果提供的证据表明，强度和持续时间是分组和突出的极好线索，但对于区分 iamb 和 trochee 本身的线索很差。总体而言，研究结果说明了 ITL 如何源自听众从单个声流中恢复两个正交感知维度（分组和突出）的方式。（PsycInfo 数据库记录 (c) 2021 APA，保留所有权利）