Zoloth S, Green S
Brain Behav Evol. 1979;16(5-6):430-42. doi: 10.1159/000121880.
Primate vocal repertoires may be classified along a continuum of discrete vs. graded signals, with the placement of a particular repertoire a result of the interplay between the species' social organization and adaptive specializations of individual signals engendered by the physical environment and their use. Discussion of the different types of graded signals reveals that they may possess either transitional, ontogenetic, or internal variability. Upon examination, the speech of humans is found to contain primarily internally graded signals, and it is suggested that the major phenomena of human speech perception are related to this internally graded quality. Based on this analysis of human speech, it is proposed that other species possessing internal gradings (e.g., Japanese macaques) are also likely to demonstrate similar perceptual phenomena for their own graded vocalizations.
灵长类动物的发声库可以沿着离散信号与分级信号的连续体进行分类，特定发声库的定位是物种社会组织与由物理环境及其使用所产生的个体信号适应性特化之间相互作用的结果。对不同类型分级信号的讨论表明，它们可能具有过渡性、个体发育性或内部变异性。经研究发现，人类的言语主要包含内部分级信号，并且有人提出，人类言语感知的主要现象与此内部分级特性有关。基于对人类言语的这一分析，有人提出，其他具有内部分级的物种（如日本猕猴）对于它们自己的分级发声也可能表现出类似的感知现象。
