- 著者
- JACOB C. DUNN
- 出版者
- The Anthropological Society of Nippon
- 雑誌
- Anthropological Science (ISSN:09187960)
- 巻号頁・発行日
- pp.180309, (Released:2018-04-03)
- 被引用文献数
- 2
One noteworthy, but unexplained, aspect of the evolution of human speech is the loss of laryngeal air sacs during hominin evolution. Very little is known about the adaptive significance of this curious trait, or the selection pressures that may have driven the evolution of air sacs among primates, and their later loss in Homo. Here, I review the literature on the loss of laryngeal air sacs during the evolution of speech, and argue that sexual selection may have been a key factor. Although air sacs do not fossilize, the presence or absence of air sacs appears to be correlated with the anatomy of the hyoid bone, and fossil hyoid evidence suggests that air sacs were lost in hominins between 3.3 million and 530000 years ago. Air sacs are hypothesized to have an acoustic function, and some authors have argued that hominins may have lost their air sacs because they would make speech less clear. In other primates, such as gorillas and howler monkeys, air sacs appear to play a role in acoustic size exaggeration and may be linked to reproductive competition. I explore the hypothesis that changes in social organization and mating system towards reduced male–male competition may have relaxed the selection pressure maintaining loud, low-frequency calls in hominins, making air sacs obsolete. While much of the above will remain hypothetical until more concrete data are gathered, we can speculate by saying that air sacs may not have been necessary for the type of quiet vocal interaction that typifies human communication. Perhaps more recent Homo species, with lower levels of sexual dimorphism and increased social tolerance and complexity, began to communicate in a more complex way, eventually leading to spoken language.
- 著者
- CHRISTIAN T. HERBST JACOB C. DUNN
- 出版者
- The Anthropological Society of Nippon
- 雑誌
- Anthropological Science (ISSN:09187960)
- 巻号頁・発行日
- vol.126, no.1, pp.19-27, 2018 (Released:2018-04-21)
- 参考文献数
- 73
- 被引用文献数
- 3
Electroglottography (EGG) is a low-cost, non-invasive method for documenting laryngeal sound production during vocalization. The EGG signal represents relative vocal fold contact area and thus delivers physiological evidence of vocal fold vibration. While the method has received much attention in human voice research over the last five decades, it has seen very little application in other mammals. Here, we give a concise overview of mammalian vocal production principles. We explain how mammalian voice production physiology and the dynamics of vocal fold vibration can be documented qualitatively and quantitatively with EGG, and we summarize and discuss key issues from research with humans. Finally, we review the limited number of studies applying EGG to non-human mammals, both in vivo and in vitro. The potential of EGG for non-invasive assessment of non-human primate vocalization is demonstrated with novel in vivo data of Cebus albifrons and Ateles chamek vocalization. These examples illustrate the great potential of EGG as a new minimally invasive tool in primate research, which can provide important insight into the ‘black box’ that is vocal production. A better understanding of vocal fold vibration across a range of taxa can provide us with a deeper understanding of several important elements of speech evolution, such as the universality of vocal production mechanisms, the independence of source and filter, the evolution of vocal control, and the relevance of non-linear phenomena.