Hauser M D, Ybarra M S
Department of Biological Anthropology, Harvard University, Cambridge, Massachusetts 02138.
Brain Lang. 1994 Feb;46(2):232-44. doi: 10.1006/brln.1994.1014.
Human and nonhuman primates commonly alter the configuration of their lips during vocal production and thereby modify vocal tract length and shape. In nonhuman primates, however, the effects of lip configuration on call structure are unknown. This study was designed to investigate the importance of lip configuration in rhesus monkey (Macaca mulatta) vocal production by temporarily blocking lip movement with injections of xylocaine. For "coo" vocalizations, an affiliative contact call that is normally produced with protruded lips, the xylocaine treatment had no statistically significant effect on call duration or characteristics of the fundamental frequency (i.e., features associated with respiration and laryngeal function). However, the two formant frequencies (i.e., features resulting from the filtering properties of the supralaryngeal cavity) of the call were significantly effected. Specifically, formant frequencies increased, as would be expected from an individual incapable of compensating for a shortened vocal tract. In contrast to coos, xylocaine had no statistically significant effect on the acoustic structure of "noisy screams," a call given in response to being attacked by a dominant and produced with retracted lips (i.e., a shortened vocal tract). Results suggest that for some vocalizations, lip configuration may be essential for achieving the intended acoustic target, whereas for other vocalizations, it is less important.
人类和非人类灵长类动物在发声时通常会改变嘴唇的形态，从而改变声道的长度和形状。然而，在非人类灵长类动物中，嘴唇形态对叫声结构的影响尚不清楚。本研究旨在通过注射赛罗卡因暂时阻断嘴唇运动，来探究嘴唇形态在恒河猴发声中的重要性。对于“咕咕叫”这种通常在嘴唇突出时发出的亲和性接触叫声，赛罗卡因处理对叫声持续时间或基频特征（即与呼吸和喉部功能相关的特征）没有统计学上的显著影响。然而，该叫声的两个共振峰频率（即由喉上腔滤波特性产生的特征）受到了显著影响。具体而言，共振峰频率增加，这与无法补偿声道缩短的个体预期情况一致。与咕咕叫不同，赛罗卡因对“嘈杂尖叫”的声学结构没有统计学上的显著影响，“嘈杂尖叫”是在受到优势个体攻击时发出的叫声，嘴唇后缩（即声道缩短）。结果表明，对于某些叫声，嘴唇形态可能对实现预期的声学目标至关重要，而对于其他叫声，其重要性则较低。
