Department of ECE, University of Maryland, College Park, MD 20742, USA.
Adv Exp Med Biol. 2013;787:183-92. doi: 10.1007/978-1-4614-1590-9_21.
We report a series of psychophysics experiments that investigated listeners' sensitivity to changes in complex acoustic scenes. Specifically, we sought to test the hypothesis that change detection is supported by sensitivity to change-related transients (an abrupt change in stimulus power within a certain frequency band, associated with the appearance or disappearance of a scene element). This hypothesis, in the context of natural scenes, is commonly dismissed on account that the elements of the scene may themselves be characterized by on-going energy fluctuations that would mask any genuine change-related transients. We created artificial 'scenes' populated by multiple pure-tone components. Tones were modulated (by a square wave at a distinct rate) so as to mimic the fluctuation properties of complex sounds. "Change" was defined as the appearance or disappearance of one such element. Importantly, such scenes lack semantic attributes, which may have been a limiting factor in interpreting previous auditory change-detection studies, thus allowing us to probe the low-level, pre-semantic, processes involved in auditory change perception. In Experiment 1 we measured listeners' ability to detect item appearance and disappearance in conditions where change-related transients are masked by a silent gap. In Experiment 2, we investigated the effect of an acoustic distractor - a brief signal that occurs at the time of change, but does not mask any scene components. The data show that gaps adversely affected the processing of item appearance but not disappearance. However, distractors reduced both -appearance and disappearance detection. Together our results suggest a role for sensitivity to transients in the process of auditory change detection, similar to what has been demonstrated for visual change detection.
我们报告了一系列心理物理学实验，这些实验旨在研究听众对复杂声音场景变化的敏感性。具体来说，我们试图检验这样一种假设，即变化检测是由对与变化相关的瞬态（刺激功率在特定频带内的突然变化，与场景元素的出现或消失有关）的敏感性支持的。在自然场景的背景下，这种假设通常被否定，因为场景的元素本身可能具有持续的能量波动，从而掩盖任何真正与变化相关的瞬态。我们创建了由多个纯音成分组成的人工“场景”。音调通过（以特定速率的方波）调制，以模拟复杂声音的波动特性。“变化”被定义为一个这样的元素的出现或消失。重要的是，这样的场景缺乏语义属性，这可能是解释先前听觉变化检测研究的一个限制因素，因此允许我们探测涉及听觉变化感知的低级、非语义过程。在实验 1 中，我们测量了听众在与变化相关的瞬态被静音间隙掩盖的情况下检测项目出现和消失的能力。在实验 2 中，我们研究了声学干扰的影响——在变化发生时出现的短暂信号，但不会掩盖任何场景成分。数据表明，间隙对项目出现的处理产生了不利影响，但对消失没有影响。然而，干扰物降低了出现和消失的检测。我们的研究结果表明，对瞬态的敏感性在听觉变化检测过程中起着作用，类似于已经在视觉变化检测中得到的结果。
