中文摘要：

在复杂声环境中，对声音强度的分辨是听觉系统对声音信号精确处理的重要功能之一．到目前为止，有关人对声音强度分辨的研究都是在单耳条件下进行的，然而，正常条件下人都是利用双耳感知强度和方位变化的声音．以人对声刺激强度的最小可察觉差异（just noticeable difference，JND）为强度分辨阈值的指标，观察双耳条件下超前声对人分辨滞后声强度的影响．实验在封闭声场中进行，声刺激强度和空间方位的控制是通过改变双耳平均声压（average binaural level，ABE）和双耳声压差（interaural level difference，ILD）来模拟的．实验结果表明，与安静条件下人对声刺激强度的分辨阈值相比，低强度的超前声对人分辨滞后声强度的阂值无显著影响，而中等及以上强度（ABL大于或等于40dB）的超前声可提高人分辨滞后声强度的阈值，闽值的提高随超前声强度的增加呈单调增大的趋势．当超前声强度一定时，超前声对人分辨滞后声强度的影响随滞后声强度的增加而衰减，对分辨较高强度的滞后声的阂值影响不显著，该结果与单耳的研究结果有明显差异．实验未发现超前声和滞后声ILD的相对改变对人探测滞后声强度变化的闽值有显著影响．

英文摘要：

In a complex acoustical environment, the ability to discriminate the level of a sound is an important function of auditory system to accurately process sound signal information. Previous studies regarding human sound level discrimination were investigated in monaural condition. However, in natural acoustical environments, human discriminate sound level and spatial information binaurally. The effect of a preceding sound was determined upon the level discrimination of a successive sound by measuring the just noticeable difference （JND） of the level of the successive sound in binaural conditions. The data were collected in close-field, dichotic acoustical conditions. The level and the spatial azimuth of both the preceding and the successive sounds were manipulated by changing the average binaural level （ABL） and the interaural level difference （ILD） of the sounds. Compared with the JND of level in quiet, low level preceding sound did not significantly change the JND of the successive sound. However, moderate and high levels （ABL ≥ 40 dB） of preceding sound significantly increased the JND of the level of the successive sound. The JNDs were monotonically increased with increasing level of the preceding sound. When the preceding sound level was constant, the effect of preceding sound on the level discrimination of the successive sound was decreased with increasing level of the successive sound, and the effect was not significant when the level of the successive sound was high. These results were different from the previous findings in monaural conditions. Also, the present study did not found a significant effect of ILD difference between the preceding and the successive sound on the level discrimination of the successive sound.