Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, United Kingdom.
J Acoust Soc Am. 2013 Jan;133(1):365-76. doi: 10.1121/1.4768798.
Spectral timbre is an acoustic feature that enables human listeners to determine the identity of a spoken vowel. Despite its importance to sound perception, little is known about the neural representation of sound timbre and few psychophysical studies have investigated timbre discrimination in non-human species. In this study, ferrets were positively conditioned to discriminate artificial vowel sounds in a two-alternative-forced-choice paradigm. Animals quickly learned to discriminate the vowel sound /u/ from /ε/ and were immediately able to generalize across a range of voice pitches. They were further tested in a series of experiments designed to assess how well they could discriminate these vowel sounds under different listening conditions. First, a series of morphed vowels was created by systematically shifting the location of the first and second formant frequencies. Second, the ferrets were tested with single formant stimuli designed to assess which spectral cues they could be using to make their decisions. Finally, vowel discrimination thresholds were derived in the presence of noise maskers presented from either the same or a different spatial location. These data indicate that ferrets show robust vowel discrimination behavior across a range of listening conditions and that this ability shares many similarities with human listeners.
光谱音色是一种声学特征，使人类听众能够确定元音的身份。尽管它对声音感知很重要，但人们对声音音色的神经表示知之甚少，很少有心理物理学研究调查非人类物种的音色辨别。在这项研究中，雪貂通过在二选一强制选择范式中积极地辨别人工元音来进行训练。动物很快学会了辨别/u/和/ε/这两个元音，并且能够立即在一系列音高范围内进行概括。然后，它们在一系列旨在评估它们在不同聆听条件下区分这些元音的能力的实验中进行了测试。首先，通过系统地移动第一和第二共振峰频率来创建一系列变形元音。其次，使用设计用于评估它们可以使用哪些频谱线索做出决策的单个共振峰刺激来测试雪貂。最后，在来自相同或不同空间位置的噪声掩蔽器存在的情况下得出了元音辨别阈值。这些数据表明，雪貂在一系列聆听条件下表现出强大的元音辨别行为，并且这种能力与人类听众有许多相似之处。
