Presentation on theme: "Origin of language: Fossil and archeological evidences Jun Hong Kim."— Presentation transcript:
Origin of language: Fossil and archeological evidences Jun Hong Kim
A few facts Oldest evidence for written language: about 6000 years ago, among relics of Sumerian civilization. Speech allows us to communicate informa tion at an exceeding rapid rate.
A few facts (cont.) Nonhuman primates do complex vocal communications. ◦ From 1980’s, previous dichotomies between human and non-human primate language abilities have gradually broken down: voluntary vs. involuntary, referential vs. indexical, graded vs. discrete, learned vs. unmodified. However, no abstract content, no grammar, inflexible in incorporating new concepts
Teaching human language to chimp and gorilla: partially succeeded: Hundreds of words, spontaneous use of signs However, they (such as Kanzi) are superior to their conspecifics in their ability to learn and use language.
Fossil Evidences No direct evidence! Because vocal tract is made up of soft tissue. Moreover, the capacity for speech is neither necessary nor sufficient for language. Articulate speech: When? Probably, early Homo.
Endocranium Language center? ◦ Broca’s area/ Wernicke’s area
Seem to better developed in early Homo ◦ Endocast of KNM-ER 1470: signs of Broca’s area (Tobias 1981, Falk 1983), Expansion in prefrontal cortex (Falk 1983) ◦ Brain lateralization: right-handedness suggest- ed by stone-tool knapping (Toth 1985). Most endocasts are incomplete or distorted. Homologues of Broca’s and Wernicke’s area are present in chimpanzee brain. Criticism
Basicranium flexion Lieberman and his associates (1972, 1991) proposed that the shape of cranial base correlates with the size of pharynx and the position of larynx. Descent of larynx during development enables human adult to make discrete sounds (such as [i], [u], [a],[k],[g]) by making vocal tract curved and large. From reconstructed hominid cast, they rebuilt laryngeal structures, estimated sound-production capability.
Source: Klein (1999)
They concluded that numerous hominid fossil, especially Neanderthals, did not have full linguistic ability. Criticism It is impossible to make certain parts from the original cast (Burr 1976). The basicranial flexion of some early Homo are within the range of that of modern human (Frayer and Nicolay 2000).
Homo ergaster may be first hominid who is able to do a degree of articulate speech. Source: Frayer and Nicolay (2000)
Gibson and Jessee (1994) failed to find con- sistent association between features of cranial base and laryngeal position in a collection of modern Americans from Texas. Langdon (2005) argues that specialized neurological control over the necessary muscles might be more important than basicranial flexion. Red deer have lowered the pharynx to make deeper and louder calls, but they cannot do complex speech. More importantly, a narrower range would not have precluded spoken language.
Size of hypoglossal canal Hypoglossal canal may be additional evidence for speech. Responsible for innervation of the tongue. (Kay et al. 1998) Australopithecines and early Homo are within the ape range.
Size of hypoglossal canal (cont.) The canal size is a poor indicator of nerve diameter because there are numerous non-human primate taxa that have hypo- glossal canals within the modern human size range (DeGusta et al. 1999).
Size of spinal cord and respiratory system Large diameter of neural canals may facilitate increased motor control of the diaphragm and intercostal muscles for the control of breathing during speech (Mac- Larnon and Hewitt 1999). Rib cage ◦ Funnel shape: chimp and Australopithecines ◦ Barrel shape: from Nariokotome boy (WT ), dated 1.6 mya.
Development of external nose has implication for speech sounds, such as some consonant produced by nasal resonance (e.g. [n]). From early Homo
Hyoid bone Kebara Neanderthal hyoid bone has completely modern shape. Accordingly, “Neanderthals appear to be anatomically capable of competent speech (Arensberg et al. 1990).” In human, hyoid bone is not directly involved in speech, although in apes it is important in some vocalization. More importantly, there are only two intact hyoid bones of hominid and their morphology is completely modern (Frayer and Nicolay 2000).
Archeological Evidence According to archeological evidence, only fully modern humans after 50kya possessed fully modern language ability. ◦ Tool making and language are sequential behavior ◦ Complex societies need arbitrary imposition of standards and patterns, which would be impossi- ble without language. ◦ Artistic expression: introspective consciousness. ◦ Symbolic behavior: use of mineral pigments, manufacture of crudely shaped figurines and carving marks on stone or bone
Why language? – Selective pressure 1. Lieberman (1984): Tradeoff between inhalation and phonation 2. Byproduct of bipedalism: basicranial flexion facilitated head balance in a bipedal posture. 3. Byproduct of climate adaptation: reshaped upper respiratory tract.
Conclusion Pace of language evolution: gradual or abrupt? When? Early Homo? Or, anatomically modern human? The use of language, as opposed to the capacity for it, may or may not have appeared at the same time.