Dorsi Josh, Viswanathan Navin, Rosenblum Lawrence D, Dias James W
1 University of California, Riverside, Riverside, CA, USA.
2 University of Kansas, Lawrence, KS, USA.
Q J Exp Psychol (Hove). 2018 Oct;71(10):2152-2161. doi: 10.1177/1747021817739257. Epub 2018 Jan 1.
The Irrelevant Sound Effect (ISE) is the finding that background sound impairs accuracy for visually presented serial recall tasks. Among various auditory backgrounds, speech typically acts as the strongest distractor. Based on the changing-state hypothesis, speech is a disruptive background because it is more complex than other nonspeech backgrounds. In the current study, we evaluate an alternative explanation by examining whether the speech-likeness of the background (speech fidelity) contributes, beyond signal complexity, to the ISE. We did this by using noise-vocoded speech as a background. In Experiment 1, we varied the complexity of the background by manipulating the number of vocoding channels. Results indicate that the ISE increases with the number of channels, suggesting that more complex signals produce greater ISEs. In Experiment 2, we varied complexity and speech fidelity independently. At each channel level, we selectively reversed a subset of channels to design a low-fidelity signal that was equated in overall complexity. Experiment 2 results indicated that speech-like noise-vocoded speech produces a larger ISE than selectively reversed noise-vocoded speech. Finally, in Experiment 3, we evaluated the locus of the speech-fidelity effect by assessing the distraction produced by these stimuli in a missing-item task. In this task, even though noise-vocoded speech disrupted task performance relative to silence, neither its complexity nor speech fidelity contributed to this effect. Together, these findings indicate a clear role for speech fidelity of the background beyond its changing-state quality and its attention capture potential.
无关声音效应（ISE）是指背景声音会损害视觉呈现的系列回忆任务的准确性这一发现。在各种听觉背景中，语音通常是最强的干扰因素。基于变化状态假说，语音是一种具有干扰性的背景，因为它比其他非语音背景更复杂。在本研究中，我们通过考察背景的语音相似度（语音保真度）是否除了信号复杂性之外还对ISE有贡献，来评估另一种解释。我们通过使用噪声声码语音作为背景来做到这一点。在实验1中，我们通过操纵声码通道的数量来改变背景的复杂性。结果表明，ISE随着通道数量的增加而增加，这表明更复杂的信号会产生更大的ISE。在实验2中，我们分别改变复杂性和语音保真度。在每个通道水平上，我们选择性地反转一部分通道，以设计出一个在整体复杂性上相等的低保真信号。实验2的结果表明，类似语音的噪声声码语音比选择性反转的噪声声码语音产生更大的ISE。最后，在实验3中，我们通过评估这些刺激在缺失项目任务中产生的干扰来评估语音保真度效应的位点。在这个任务中，尽管噪声声码语音相对于安静状态会干扰任务表现，但其复杂性和语音保真度都对此效应没有贡献。总之，这些发现表明背景的语音保真度除了其变化状态质量和吸引注意力的潜力之外，还有一个明确的作用。
