Freyman Richard L, Zurek Patrick M
Department of Communication Disorders, University of Massachusetts, 358 North Pleasant Street, Amherst, Massachusetts 01003, USA.
Sensimetrics Corporation, 14 Summer Street, Suite 403, Malden, Massachusetts 02148, USA.
J Acoust Soc Am. 2017 Jul;142(1):206. doi: 10.1121/1.4990020.
This study describes the contributions to auditory image position of an interaural time delay (ITD) cue at onset relative to subsequent ITDs during the ongoing part of a stimulus. Test stimuli were trains of 1-ms binaural noise bursts; lateral position was measured with a wideband acoustic pointer that subjects adjusted to match the intracranial position of test stimuli. In different conditions the ongoing part of the stimulus (the bursts following the first one) either had a consistent ITD (the same ITD on each ongoing burst), or had alternating leading and lagging components with ITDs that opposed one another. As duration of the ongoing part was increased from 4 to 250 ms, with the initial ITD fixed, lateral position changed from being dominated by the onset ITD to being dominated by the ongoing consistent or leading ITD. With alternating ongoing ITDs equal contributions from onset and ongoing parts were obtained at an ongoing duration of about 40 ms; with consistent ongoing ITDs equal contributions were obtained at about 15 ms. The results point up the increased dominance of onset cues when ongoing cues are ambiguous, as they often are in real-world settings.
本研究描述了在刺激持续过程中，起始时的双耳时间延迟（ITD）线索相对于后续ITD对听觉图像位置的贡献。测试刺激为1毫秒的双耳噪声脉冲序列；通过宽带声学指针测量侧向位置，受试者对其进行调整以匹配测试刺激的颅内位置。在不同条件下，刺激的持续部分（第一个脉冲之后的脉冲）要么具有一致的ITD（每个持续脉冲上的ITD相同），要么具有交替的领先和滞后成分，其ITD相互对立。随着持续部分的持续时间从4毫秒增加到250毫秒，初始ITD固定，侧向位置从由起始ITD主导变为由持续一致或领先的ITD主导。对于交替的持续ITD，在持续时间约为40毫秒时，起始和持续部分的贡献相等；对于一致的持续ITD，在约15毫秒时贡献相等。结果表明，当持续线索模糊时，起始线索的主导作用增强，而在现实世界环境中持续线索往往是模糊的。
