Download Origin of language: (at least) 4 ways of thinking

Origin of language: (at least) 4 ways of
thinking
Punctuationist
Naîve
Evolutionist
Pre-adaptationist;
Exaptationist
Exaptationist
AND
Cultural
evolutionist
Language
Sub-faculties to be considered
Language
Faculties of vocal learning, syntax, and semantics (at least)
merged together to enable language
Okanoya, 2006
Sub-faculties and exaptations
 
Vocal Learning
 
 
Syntax
 
 
From intentional respiratory control
From sexual displays that are sequentially
organized, such as dance and song
Semantics
From hard-wired, situation specific communication
signals (i.e, alarm calls)
  To meaningful action coordination
 
Species that show vocal learning
 
81 species of whales
 
~5000 species out of
~9000 species of birds
(songbirds, parrots, and
humming birds)
 
Only one species of
primates out of ~220
Okanoya, 2010
Species that learn vocalizations
 
 
 
 
Some whales
Some birds
One primate (!)
Common anatomical
feature: Direct pathway from
motor cortex to medullar
respiratory/vocal nuclei
Okanoya, 2006
Reasons for having the direct path
 
Birds and whales: accurate respiratory control
when flying or submerging
 
Humans: ????
 
Baby cry hypothesis (Okanoya et al 2002)
  No
other primates cry as much as human babies
  No risk of predation by crying
  Manipulation of caregivers via crying was effective
Okanoya, 2006
Cry development in human infants
1d
18d
1M
Baby cries begin as repetitions
of simple elements.
Baby cries become complex
both acoustically and
syntactically after 1 month.
This maybe related with
myelinization of the direct
pathway.
4M
Okanoya, 2006
Mutual segmentation of baby cry and
mother semantics
Okanoya, 2006
Example 1: Evolution of
Language via Gesture
From gestures to language
Not a new idea, really (Condillac, 1746)
  “Sign languages” (W. Stokoe)
  “From Hand to Mouth” (M. Corballis)
  Etc.
 
Example 2: Evolution of Language
via Syntax (and vocalization)
Birdsong syntax
 
Song is a sexual behavior: sung in a mating context
Okanoya, 2006
Song syntax in two strains of birds
 
Munia (left) and its
domesticated form,
Bengalese
 
Bengalese Finch sings
complex songs
 
Munia sings simple
songs
Okanoya, 2006
Handicap Principle (Amotz Zahavi)
It takes some effort to maintain excessive ornaments. Surviving with
such excessive ornaments implies that the individual must have higher
survival value and such males are selected by females. Excessive
ornaments can then be indicators of the fitness.
Bengalese finch mating song
Bengalese finch song
Only males sing to seduce females.
  Learning takes place when birds are at
juvenile stage.
  Learning proceed in two phases: sensory
phase and sensory-motor phase.
  Cortex- basal ganglia pathway for song
learning.
  It can be expressed by a Finite-state syntax
 
Finite-state song syntax in
Bengalese finches
In this example,
ab, cde, and fg
are organized into
“chunks”. These
three chunks are
sung in various
orders.
Song learning in a multi-tutor environment
1st generation Male A
1st generation Male B
2nd generation
1st generation Male C
Takahasi
2010
Ethology
Brain of the Bengalese finch
LMAN
NIf
HVc
Lateral
NIf
AreaX
RA
Medial
OKANOYA Lab.
Bilateral NIf Lesion simplified Syntactical
Song
Before
After
Hosino & Okanoya, 2000
Birdsong studies: Summary
 
Juvenile Bengalese finches segment parts of
songs from multiple tutors and recombine
these to invent their original songs.
 
To sing normal songs, avian forebrain areas
equivalent to human inferior frontal cortex and
basal ganglia are necessary.
Cost of complex song syntax
 
 
 
 
 
Predation
Time to find food
Neural substrates (more brain space)
Higher testosterone level (harms immune system)
Need to maintain fine muscle tune
First two points could be
masked by domestication
Functional un-grounding:
Spotted Munia, a sympatric species
of white-backed munias in Taiwan
Field work: Taiwan study site
T: Taipei
H:Huben
（Suburban）
(Woods)
Mountain running
South to North
M:Mataian
（Rice field)
More sympatric species, more linear
(less complex) songs
Song linearity
H < M, T
Sympatric ratio
H < M, T
Effect of sympatric species
  Higher
sympatric ratio is correlated with
lower song complexity.
  Interpretation:
songs cannot be complex
to secure species identification.
  Domestication
is a special case in which
no sympatric species exist.
Degeneration of species identification
led to evolution of syntactical
complexity?
1. 
2. 
Domestication degenerated constraints
By domestication, several constraints
(species recognition, social learning) against
developing complex, elaborated songs are
masked.
Domestication promoted Sexual Selection
Female choice for complex song syntax is
strongly promoted by domestication.
Degeneration by self-domestication
as a driving force
for Human Language evolution?
wild
wild
domestic
domestic
Some points
 
Possible biological exaptations for language
Vocal plasticity > vocal learning
  String segmentation > syntax
  Context segmentation > semantics
 
 
A mechanism for signal complexity
 
Functional un-grounding increases complexity
(e.g., “domestication”)
Evolution of Language:
Some conclusions
 
Most efforts (overemphasis?) have been
dedicated to investigate grammar/syntax and
phonology/vocalization
 
Crucial ingredients that are under-represented
… (or ignored). The inherent role of:
1. 
2. 
3. 
Semantics (i.e., meaning emergence, not just
lexical, sentential, propositional)
Co-speech motor action (e.g., gesture)
Coordination of top-down mechanisms (e.g.,
cultural evolution)