U.S. Navy Marine Mammal Program, Space and Naval Warfare Systems Center Pacific, Code 71510, 53560 Hull Street, San Diego, California 92152, USA.
J Acoust Soc Am. 2011 Nov;130(5):3124-36. doi: 10.1121/1.3641449.
Loudness level measurements in human listeners are straightforward; however, it is difficult to convey the concepts of loudness matching or loudness comparison to (non-human) animals. For this reason, prior studies have relied upon objective measurements, such as response latency, to estimate equal loudness contours in animals. In this study, a bottlenose dolphin was trained to perform a loudness comparison test, where the listener indicates which of two sequential tones is louder. To enable reward of the dolphin, most trials featured tones with identical or similar frequencies, but relatively large sound pressure level differences, so that the loudness relationship was known. A relatively small percentage of trials were "probe" trials, with tone pairs whose loudness relationship was not known. Responses to the probe trials were used to construct psychometric functions describing the loudness relationship between a tone at a particular frequency and sound pressure level and that of a reference tone at 10 kHz with a sound pressure level of 90, 105, or 115 dB re 1 μPa. The loudness relationships were then used to construct equal loudness contours and auditory weighting functions that can be used to predict the frequency-dependent effects of noise on odontocetes.
在人类听众中进行响度水平测量是很直接的；然而，向（非人类）动物传达响度匹配或响度比较的概念却很困难。出于这个原因，先前的研究依赖于客观测量，如反应潜伏期，来估计动物的等响曲线。在这项研究中，一只宽吻海豚被训练来进行响度比较测试，在该测试中，听众要指出两个连续的音调中哪一个更响亮。为了奖励海豚，大多数试验都采用了具有相同或相似频率但相对较大声压级差异的音调，因此响度关系是已知的。只有一小部分试验是“探针”试验，采用的音调对其响度关系是未知的。对探针试验的反应被用来构建心理物理函数，描述特定频率的音调与 10 kHz 参考音调的响度关系，该参考音调的声压级为 90、105 或 115 dB 相对于 1 μPa。然后，这些响度关系被用来构建等响曲线和听觉加权函数，可用于预测噪声对齿鲸的频率相关影响。
