Oldfield S R, Parker S P
Perception. 1986;15(1):67-81. doi: 10.1068/p150067.
A study is reported in which the acuity of azimuth and elevation discrimination under monaural listening conditions was measured. Six subjects localised a sound source (white noise through a speaker) which varied in position over a range of elevations (-40 degrees to +40 degrees) and azimuths (0 degrees to 180 degrees), at 10 degrees intervals, on the left side of the head. Monaural listening conditions were established by the fitting of an ear defender and one earmuff to the right ear. The absolute and algebraic, azimuth and elevation errors were measured for all subjects at each position of the source. The results indicate that all subjects suffered a marked reduction of azimuth acuity under monaural conditions, although a coarse capacity to discriminate azimuth still remained. Considerable between-subject variability was observed. Front/back discrimination was retained, although it was slightly impaired compared to that observed under normal listening conditions. Elevation discrimination was, on the whole, quite good under monaural conditions. However, a comparison of the performance of these subjects under monaural conditions with that observed under normal listening conditions indicated that some reduction in elevation localisation acuity occurred in the frontal quadrants in the median plane and in the upper quadrants of more lateral source positions. The reduction in acuity seen in these regions is attributed to the loss of information from the pinna of the occluded ear rather than to the observed reduction in azimuth error. The results provide partial support for the binaural pinna disparity model.
本文报告了一项关于单耳聆听条件下方位角和仰角辨别敏锐度的研究。六名受试者定位一个声源（通过扬声器发出的白噪声），该声源在头部左侧的一系列仰角（-40度至+40度）和方位角（0度至180度）范围内以10度间隔变化位置。通过给右耳佩戴一个护耳器和一个耳罩来建立单耳聆听条件。在声源的每个位置测量所有受试者的绝对和代数方位角及仰角误差。结果表明，所有受试者在单耳条件下方位角敏锐度都显著降低，尽管仍保留了一定的辨别方位的粗略能力。观察到受试者之间存在相当大的变异性。前后辨别能力得以保留，尽管与正常聆听条件下观察到的相比略有受损。总体而言，单耳条件下仰角辨别相当良好。然而，将这些受试者在单耳条件下的表现与正常聆听条件下观察到的表现进行比较表明，在正中平面的额象限以及更外侧声源位置的上象限，仰角定位敏锐度出现了一些降低。在这些区域观察到的敏锐度降低归因于被遮挡耳朵耳廓信息的丢失，而非观察到的方位角误差的降低。这些结果为双耳耳廓差异模型提供了部分支持。
