Transcript Lecture 4 - On the Evolution of Human Language

Linguistic Anthropology
ON
THE EVOLUTION OF LANGUAGE
LANGUAGE IS A HUMAN UNIVERSAL

Found in all human groups

Develops along similar lines in all children

Can even develop in individuals with
impairments

A product of human evolution
FOSSIL RECORD
ARCHAEOLOGICAL RECORD
TYPES OF PALEO-EVIDENCE
ANATOMICAL BASES OF SPOKEN LANGUAGE
THE HUMAN VOCAL TRACT

Pharynx
 Back
of throat
 space for tongue

Larynx
 Location
of vocal cords
THE HUMAN VOCAL TRACT

Human infants born with high larynx
 Begins
to lower at three months
 Reaches adult location by 3-4 years
 Except
in adult males: further descent at adolescence.
THE HUMAN VOCAL TRACT

Lowering of the larynx


Adult humans cannot
breathe and swallow at
the same time
Lengthening of the
pharynx


Provides more space
for tongue
Enables increased
vowel resonance

Differentiation of vowels:
[i] [a] [u]
THE HYOID BONE
a.k.a. the ”lingual bone”
Does not directly articulate
with other bones
THE HYOID BONE IN OTHER ANIMALS
Red Howler Monkey
(Alouatta seniculus)
THE HYOID BONE IN OTHER ANIMALS
Position of hyoid bones (shaded) with tongue retracted (A) and
extended (B), shown in the hairy woodpecker (Dendrocopos
villosus).
The hyoid apparatus
and skull of a flicker
(Colaptes sp.)
Northern Flicker
(Colaptes auratus)
THE NEANDERTHAL HYOID BONE
Torso (left) and hyoid bone (above) of
Neanderthal individual known as Kebara 2
ca. 60,000 B.P.
(Kebara Cave, Israel)
COMPARING THE HYOIDS
COULD THE NEANDERTHALS SPEAK?

Morphology of hyoid bone is essentially modern

Lack of preserved soft tissue makes it difficult
to assess whether the rest of the Neanderthal
vocal apparatus was like that of modern
humans

The short answer: we cannot yet say…
THE HUMAN BRAIN

Cortex




Convoluted surface of the brain
Two millimeters thick
Surface area 1.5 square yards
Contains 100 million neurons

Oldest part of cortex



Controls long term memory
and emotion
Newer part of cortex




“Neocortex”
Controls language
80% of human brain
Divided (by sulci) into lobes




Frontal
Temporal
Parietal
Occipital
LANGUAGE AREAS OF THE BRAIN

Broca’s area
 Clarity
of speech
 Function words
 Some word order

Wernicke’s area
 Understanding
words
 Producing
sentences
BRAIN ENDOCASTS
Fossilized face (left) and cranial endocast (right) of the “Taung” child
(Australopithecus africanus)
BRAIN ENDOCASTS
Endocasts of several
Australopithecus specimens

Reveal details of the
brain case, which in turn
reflect some detail of the
brain’s surface

Do not provide an
indication of the internal
structures or architecture
of the brain
BRAIN ENDOCASTS

Position of lunate sulcus
posterior in
Australopithecus

Anterior to lunate sulcus:
posterior parietal
cerebral cortex

Responsible in humans
for object appreciation,
facial recognition, and
social communication
Endocast of Stw 505 (A. africanus)
(Sterkfontein, South Africa)
(ca. 3 mya – 2 mya)
BRAIN ENDOCASTS
Above: Virtual endocast of LB1 (Homo Floresiensis)
Right: LB1 (middle); mcHS (microcephalic
Homo sapiens) HS (Homo sapiens);
He (Homo erectus); PT (Pan troglodytes)
BRAIN ENDOCASTS

Indicate aspects of
brain reorganization
that may have led to the
development of features
now associated with
language

Do not demonstrate
that these features
were used for language
Reconstructed brain and endocast of
Zhoukoudian V (Homo erectus)
(ca. 400,000-500,000 ya)
FOXP2 (FORKHEAD BOX P2) GENE




Vernes SC, Oliver PL, Spiteri E, Lockstone HE, Puliyadi R, et al. (2011) Foxp2 Regulates
Gene Networks Implicated in Neurite Outgrowth in the Developing Brain. PLoS Genet
7(7) http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1002145;
accessed 2 Sept. 2013

Point mutation in humans
results in
defects in the grammatical
processing of words
difficulties understanding
complex sentence structures
inability to form intelligible
speech
defects in the ability to move
the mouth and face not
associated with speaking
significantly reduced IQ
FOXP2 (FORKHEAD BOX P2) GENE



Image modified from Enard et al, 'Molecular evolution of FOXP2, a gene involved in
speech and language', Nature 418, 869 - 872, (2002); found at
http://www.evolutionpages.com/FOXP2_language.htm; accessed 2 September 2013.


Chromosome 7
Codes for transcription
factor (protein that
regulates neural
development)
715 amino acids
Difference of 2 amino
acids in chimpanzee
vs. human proteins
Mutation likely arose
10,000-100,000 yBP
CULTURAL EVIDENCE OF LANGUAGE USE
CULTURAL EVIDENCE - HANDAXES
550 kya
north-east Norfolk, England
How to make a handaxe
250 to 500 kya
Franschhoek, South Africa
CULTURAL EVIDENCE - ART
Blombos Cave - Ochre Tablet
Ca. 73 kya
Acheulean figurine, Israel
ca. 230 kya
Blombos Cave Shell Beads
ca. 73 kya
CULTURAL EVIDENCE - ART
Hyena – Chauvet Cave, France
ca. 32 kya
CULTURAL EVIDENCE - WRITING
Harappa
Ca. 5,500 B.P.
Egypt
Ca. 5,300 – 5,200 B.P.
Left: Cuneiform text, Mesopotamia
Ca. 5,100 B.P.
WHAT CAN WE SAY?

We cannot clearly determine when human
language first emerged

Both anatomical and artifactual material
suggests that human intelligence evolved in a
series of steps

A gradual emergence? A “final” step? We do
not yet know…