Roberts Richard A, Koehnke Janet, Besing Joan
Department of Communication Sciences and Disorders, University of South Florida, 4202 East Fowler Avenue, PCD 1017, Tampa, FL 33620, USA.
Hear Res. 2004 Jan;187(1-2):73-84. doi: 10.1016/s0378-5955(03)00337-x.
The purpose of this investigation was to determine the effects of reverberation on the precedence effect by obtaining thresholds for perception of leading and lagging noise burst stimuli as separate auditory events. In Experiment 1, lag burst thresholds for 4-ms noise bursts were measured in a simulated reverberant and anechoic environment for nine subjects with normal hearing at presentation levels of 10, 20, and 30 dB SL. Results indicated that lag burst thresholds obtained in the reverberant environment were higher than those obtained in the anechoic environment, with no effect of sensation level. In Experiment 2, three new stimulus conditions, two monaural and one binaural control, were employed. For one monaural condition, the stimuli were equal in level and for the other, the leading stimulus was more intense than the lagging stimulus. For the binaural control condition, the stimuli were presented from a perceived spatial location of 0 degrees azimuth. In the monaural and binaural control conditions, lag burst thresholds were lower than those obtained in the reverberant environment of Experiment 1. There was no difference between lag burst thresholds obtained in either environment for the monaural and binaural control conditions compared to the anechoic condition of Experiment 1. Results of Experiment 2 indicate that the higher lag burst thresholds observed in Experiment 1 are not fully explained by a peripheral masking effect.
本研究的目的是通过获取领先和滞后噪声突发刺激作为单独听觉事件的感知阈值，来确定混响对优先效应的影响。在实验1中，针对9名听力正常的受试者，在模拟混响和无回声环境中，于10、20和30 dB SL的呈现水平下测量了4毫秒噪声突发的滞后突发阈值。结果表明，在混响环境中获得的滞后突发阈值高于在无回声环境中获得的阈值，且感觉水平无影响。在实验2中，采用了三种新的刺激条件，两种单耳条件和一种双耳对照条件。对于一种单耳条件，刺激强度相等；对于另一种单耳条件，领先刺激比滞后刺激更强。对于双耳对照条件，刺激从0度方位角的感知空间位置呈现。在单耳和双耳对照条件下，滞后突发阈值低于实验1混响环境中获得的阈值。与实验1的无回声条件相比，单耳和双耳对照条件在任一环境中获得的滞后突发阈值之间没有差异。实验2的结果表明，实验1中观察到的较高滞后突发阈值不能完全由外周掩蔽效应来解释。
