The basicranium of Plio‐Pleistocene hominids as an indicator of their upper respiratory systems

Laitman, Jeffrey T.; Heimbuch, Raymond C.

doi:10.1002/ajpa.1330590315

Cited by 136 publications

(62 citation statements)

References 23 publications

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“…The second phase of descent was possibly related to skeletal developments that evolved during hominid evolution, such as the ventral flexion of the cranial base during infant and early juvenile development (2,11,12,37), reduced prognathism caused by sphenoidal shortening (9), and increases in mandibular height (6). Furthermore, the shorter oral component of the SVT H in humans also contributes to a decrease in the ratio of SVT H to SVT V .…”

Section: Discussionmentioning

confidence: 99%

“…This concept has formed a basis for paleoanthropological studies on the origin and evolution of human speech, in which the ''unique'' morphological features related to speech have been examined through comparisons with extant primates (2,(11)(12)(13)(14)(15)(16). Thus, the evolution of the morphological basis for human speech has been regarded as synonymous with the evolution of the developmental descent of the larynx.…”

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confidence: 99%

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Descent of the larynx in chimpanzee infants

Nishimura

Mikami

Suzuki

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

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The human larynx descends during infancy and the early juvenile periods, and this greatly contributes to the morphological foundations of speech development. This developmental phenomenon is believed to be unique to humans. This concept has formed a basis for paleoanthropological studies on the origin and evolution of human speech. We used magnetic resonance imaging to study the development of three living chimpanzees and found that their larynges also descend during infancy, as in human infants. This descent was completed primarily through the rapid descent of the laryngeal skeleton relative to the hyoid, but it was not accompanied by the descent of the hyoid itself. The descent is possibly associated with developmental changes of the swallowing mechanism. Moreover, it contributes physically to an increased independence between the processes of phonation and articulation for vocalization. Thus, the descent of the larynx and the morphological foundations for speech production must have evolved in part during hominoid evolution, and not in a single shift during hominid evolution. In the human neonate, the hyoid bone and larynx are positioned as high as in other mammals (1-3). However, they descend gradually during postnatal life (1-6). This descent is completed through the descent of the laryngeal skeleton relative to the hyoid and the descent of the hyoid relative to the mandible and cranial base (4-6). Thus, the human supralaryngeal vocal tract (SVT) develops to form a double resonator system with equally long horizontal [SVT H , from the posterior oropharyngeal wall (POW) to the lips] and vertical (SVT V , from the vocal folds to the velum) components (2, 6). Acoustically, such a configuration, in combination with the tongue's mobility, enables humans to produce complex speech sounds (7,8).It is commonly assumed that this developmental descent evolved as an adaptation for speech in a single shift in the human lineage, in combination with decreased prognathism and flexure of the cranial base (2, 9, 10). This concept has formed a basis for paleoanthropological studies on the origin and evolution of human speech, in which the ''unique'' morphological features related to speech have been examined through comparisons with extant primates (2,(11)(12)(13)(14)(15)(16). Thus, the evolution of the morphological basis for human speech has been regarded as synonymous with the evolution of the developmental descent of the larynx. Nonetheless, there are few comparative studies on the developmental changes of humans and non-human mammals (17-19), and it is unclear how and when the unique features of the speech apparatus of adult humans appear and develop during growth. Subjects and MethodsMagnetic Resonance Imaging (MRI) Procedures. We used MRI technology to examine the developmental changes of the SVT shape in three living chimpanzee infants, named Ayumu (male), Cleo (female), and Pal (female). They were born in 2000 and were reared by their biological mothers in the Kyoto University Primate Research Institute (KUPRI) (20,2...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Descent of the larynx in chimpanzee infants

Nishimura

Mikami

Suzuki

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

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“…More recently, efforts have been made to reconstruct the shapes of hominid vocal tracts (upper respiratory systems) from bony landmarks of the basicranium (9)(10)(11)(12). On the basis of these reconstructions, it has been claimed that Neanderthals and earlier hominids may not have produced the full range of sounds of the sort humans produce today.…”

Section: Previous Evidence For Language Originsmentioning

confidence: 99%

The hypoglossal canal and the origin of human vocal behavior

Kay

Cartmill²,

Balow³

1998

Proc. Natl. Acad. Sci. U.S.A.

123

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The mammalian hypoglossal canal transmits the nerve that supplies the muscles of the tongue. This canal is absolutely and relatively larger in modern humans than it is in the African apes (Pan and Gorilla). We hypothesize that the human tongue is supplied more richly with motor nerves than are those of living apes and propose that canal size in fossil hominids may provide an indication about the motor coordination of the tongue and ref lect the evolution of speech and language. Canals of gracile Australopithecus, and possibly Homo habilis, fall within the range of extant Pan and are significantly smaller than those of modern Homo. The canals of Neanderthals and an early ''modern'' Homo sapiens (Skhul 5), as well as of African and European middle Pleistocene Homo (Kabwe and Swanscombe), fall within the range of extant Homo and are significantly larger than those of Pan troglodytes. These anatomical findings suggest that the vocal capabilities of Neanderthals were the same as those of humans today. Furthermore, the vocal abilities of Australopithecus were not advanced significantly over those of chimpanzees whereas those of Homo may have been essentially modern by at least 400,000 years ago. Thus, human vocal abilities may have appeared much earlier in time than the first archaeological evidence for symbolic behavior. Previous Evidence for Language OriginsLanguage is arguably the most important behavioral attribute that distinguishes humans from other animals. It is indispensable in many complex human social relations, including the planning and coordination of group activities. Language is widely regarded as a prerequisite for deliberative thought and action, self-awareness, or even simple sentience. Because other animals lack language, it is difficult to identify behavioral and anatomical correlates that indicate its first appearance in human evolution. Some have sought to infer language ability from archaeological evidence of subsistence activities that seem to have involved collective decision-making (e.g., biggame hunting) or of structural complexity and diversity in the design of occupation sites (1-4). The appearance of body ornamentation and deliberate burial practices in the late Pleistocene have been identified with consciousness and the awareness of self, thought by some to imply language abilities (5), and the first appearance of unambiguous symbols in the archaeological record, within the last 40,000 years, has been taken by some (1) as marking the first definite evidence for the presence of human language.Early attempts to infer the presence or absence of humanlike speech abilities from such anatomical features of fossil hominids as the presence of a chin or the development of the mylohyoid ridge on the inside of the lower jaw (6, 7) have not been widely credited with success (4, 8). More recently, efforts have been made to reconstruct the shapes of hominid vocal tracts (upper respiratory systems) from bony landmarks of the basicranium (9-12). On the basis of these reconstructions, it has bee...

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“…In a series of papers, Laitman, Crelin, and colleagues have carefully demonstrated the sequence of developmental changes in soft tissue and skeletal anatomy of the basicranium, upper respiratory system, and vocal tract region in modern humans as compared to fossil hominids and nonhuman primates (e.g., Crelin, 1976, 1980;Laitman et al, 1978Laitman et al, , 1979Laitman and Heimbuch, 1982 flexion characteristic of adult human basicrania taken to be evidence of neotenic paedomorphosis actually develops during postnatal growth as the tongue and larynx descend in the neck (i.e., human adult morphology changes considerably from that characterizing the fetal condition of humans and nonhuman primates alike). In fact, Laitman and Heimbuch's (1984) data demonstrate less change in basicranial angles and linear measures from juvenile to adult stages in Pan paniscus than in Homo sapiens (Fig.…”

Section: Growth Prolongation Us Shape Retardationmentioning

confidence: 99%

Heterochrony in human evolution: The case for neoteny reconsidered

Shea

1989

Am. J. Phys. Anthropol.

192

110

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This paper reviews the evidence for the claim that neoteny, or morphological juvenilization resulting from dissociation and retardation of ancestral rates of shape change, has played a key role in human evolution. Accepted categories and processes of heterochrony are reviewed, and the available data on human growth, variation, and evolution are analyzed in light of expected results. Relatively weak concordance with predictions is found. Mistakes of fact and interpretation fall into several categories, including 1) confusion of neoteny with paedomorphosis resulting from other heterochronic processes; 2) conflation of growth prolongation in time with morphological shape retardation; 3) failure to move beyond superficial shape similarities to underlying homologous growth processes and patterns; 4) failure to identify a paedomorphic basis for key anatomical novelties in human evolution; and 5) establishing an essentially untestable framework for analysis of the hypothesis. Key areas that might contribute new data to this debate are discussed, particularly the genetic and epigenetic control of the covariation of morphology and development during ontogeny and evolution. The primary reasons that arguments in favor of neoteny in human evolution have persisted probably relate to anthropocentric factors and the search for a single basis for the important morphological and behavioral transformations characterizing our lineage.The claim that neoteny has played a central role in human evolution has spawned one of the most persistent and vexing debates in physical anthropology over the past century. Treatments ranging from focused morphological investigations to major theoretical treatises have been produced, but little in the way of consensus and resolution has emerged. How, therefore, can we justify yet another review of this problem? I attempt such a justification along several lines. First, the volume of ink spilled over this topic is hardly evenly divided between pro and con-advocates outnumber detractors, at least in the published literature of the past several decades. I will argue here that there are numerous inconsistencies in these arguments that have never been pointed out, sufficiently stressed, or synthesized. Second, there is a considerable amount of new information germane to this issue that has been produced in the decade since the last major review of human neoteny, that by Gould (1977). Most of this information comes from outside the study of human evolution, but it is directly relevant to the question of human neoteny nonetheless. Finally, rather than simply attempting to offer a resolution or the "final word" on this topic, I will try to point out the areas of critical knowledge that are lacking and that would contribute to a better understanding of this and related issues. Because most previous authors have strongly and defensively 0 1989 Alan R. Liss, Inc. YEARBOOK OF PHYSICAL ANTHROPOLOGY[Vol. 32, 1989 advocated a particular view in this debate, there has been relatively little consideration...

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The basicranium of Plio‐Pleistocene hominids as an indicator of their upper respiratory systems

Cited by 136 publications

References 23 publications

Descent of the larynx in chimpanzee infants

Descent of the larynx in chimpanzee infants

The hypoglossal canal and the origin of human vocal behavior

Heterochrony in human evolution: The case for neoteny reconsidered

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