Center for Hearing Research, Boys Town National Research Hospital, 555 North 30th Street, Omaha, Nebraska 68131, USA.
J Acoust Soc Am. 2011 Apr;129(4):2095-103. doi: 10.1121/1.3557043.
The detection of a brief increment in the intensity of a longer duration pedestal is commonly used as a measure of intensity-resolution. Increment detection is known to improve with increasing duration of the increment and also with increasing duration of the pedestal, but the relative effects of these two parameters have not been explored in the same study. In several past studies of the effects of increment duration, pedestal duration was increased as increment duration increased. In the present study, increment and pedestal duration were independently manipulated. Increment-detection thresholds were determined for four subjects with normal-hearing using a 500- or 4000-Hz pedestal presented at 60 dB sound pressure level (SPL). Increment durations were 10, 20, 40, 80, 160, and 320 ms. Pedestal durations were 20, 40, 80, 160, and 320 ms. Each increment duration was combined with all pedestals of equal or greater duration. Multiple-regression analyses indicate that increment detection under these conditions is determined primarily by pedestal duration. Follow-up experiments ruled out effects of off-frequency listening or overshoot. The results suggest that effects of increment duration have been confounded by effects of pedestal duration in studies that co-varied increment and pedestal duration. Implications for models of temporal integration are discussed.
检测较长持续时间基音上短暂的强度增量通常被用作强度分辨率的度量。已知增量检测随增量持续时间的增加而提高，也随基音持续时间的增加而提高，但这两个参数的相对影响在同一研究中尚未得到探讨。在过去的几项关于增量持续时间影响的研究中，随着增量持续时间的增加，基音持续时间也随之增加。在本研究中，增量和基音持续时间是独立操作的。使用 500 或 4000 Hz 基音，在 60 dB 声压级 (SPL) 下，对 4 名听力正常的受试者进行了增量检测阈值的测定。增量持续时间分别为 10、20、40、80、160 和 320 ms。基音持续时间分别为 20、40、80、160 和 320 ms。每个增量持续时间与相等或更长的基音组合。多元回归分析表明，在这些条件下的增量检测主要由基音持续时间决定。后续实验排除了离频聆听或过冲的影响。结果表明，在同时改变增量和基音持续时间的研究中，增量持续时间的影响被基音持续时间的影响所混淆。讨论了对时间整合模型的影响。
