Transcript Fig 1 - University of Memphis

An evo-devo perspective on the evolution of language:
How early human vocal development can provide guidance
D. Kimbrough Oller
The University of Memphis, Memphis, TN, USA
School of Communication Sciences and Disorders and Institute for Intelligent Systems
and
The Konrad Lorenz Institute for Evolution and Cognition Research, Klosterneuburg, Austria
Infant Vocalization and
Language Evolution Research
University of Memphis
Collaborators
– Eugene Buder
– Ulrike Griebel
– Edina Bene
External Collaborating Faculty
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Rick Dale, University of California, Merced
Suneeti Nathani Iyer, University of Georgia
Anne Warlaumont, University of California, Merced
Rafael Delgado, Intelligent Hearing Systems, Miami
Partha Niyogi (deceased), University of Chicago
Mary Pat Moeller, Boys Town Natl. Research Hospital
Peter Mundy, University of CA, Davis (MIND Institute)
Elena Patten, University of North Carolina, Greensboro
Roger Bakeman, Georgia State University
Li-Mei Chen, National Cheng Kung University., Taiwan
Heather Ramsdell, Idaho State University
Daniel Messinger, University of Miami
Steven F. Warren, University of Kansas
Alan Cobo-Lewis, University of Maine
Paul Yoder, Vanderbilt University
Michael Owren (deceased), Emory University
Ofer Tchernichovski, CUNY, Hunter College
Betty Vohr, Brown University
Josep Call, Max Planck Inst. for Evolutionary Anthro., Leipzig
How to describe very early human infant
vocalizations (and infant speech perception)
• Both the linguistic tradition of Jakobson and
his followers and a largely independent
psychology tradition assumed one could
categorize infant sounds by phonetic
transcription
• This yielded generations of false beliefs
• The appropriate alternative is to treat the
issue as embryologists treat the very early
stages of zygote development
Sprouts of cherry trees
Preformationism and epigenetics
Radical Preformationism
Nicolas Hartsoeker claimed to have
found “animacules” in semen of
humans and other animals.
This led to spermist theory, the
belief that sperm was a "little man"
that after placement in a woman
would grow into a child.
Most famous depictions of
the homunculus
N. Hartsoecker , 1695
By no later than the middle of the 17th century a
preformationist/epigenetic argument about
embryology was active. William Harvey had posited a
view that had an epigenetic flavor…
But to imagine that unorganized matter might selforganize into life ran afoul of Cartesianism, the
dominant view. Since there was no available
mechanical explanation for epigenesis, it became
common to posit preformed miniature organisms
expanding in accordance with mechanical laws. So
some naturalists claimed to see miniature preformed
animals (animacules) in eggs and miniature plants in
seeds.
Antonie van Leeuwenhoek (middle of the 17th century) was one of the
first to observe spermatozoa. He described the spermatozoa of about 30
species, and thought he saw in semen, "all manner of great and small
vessels, so various and so numerous that I do not doubt that they be
nerves, arteries and veins...And when I saw them, I felt convinced that,
in no full grown body, are there any vessels which may not be found
likewise in semen."
One theorist posited that each embryo could contain even
smaller embryos ad infinitum, like a Matryoshka doll.
For two centuries, until the invention of cell theory, preformationists
would oppose epigenicists, with two preformationist thrusts:
spermists claimed the homunculus must come from the spermatozoa
while ovists thought they were in the ova.
Artistic rendering
of the zygote as a
vessel
A more modern view:
Preformationist gene to trait mapping
Trait1
Trait2
Trait3
Trait4
Trait5
Gene1 Gene2 Gene3
Gene4
Gene5 ……… Genen
……….
Traitn
More modern preformationism
This view often goes hand in hand with extreme
nativist claims, and these can lead to the
postulation of innate capabilities or modules of
function, such as the LAD.
Such modules are assumed products of the
genes, with little if any role accorded to learning
or other forms of epigenesis
A triggering function is the only role usually posited
for the environment in such a radical nativist view
Oskar Hertwig at the end of the nineteenth century complained that
August Weismann's germ-cell predetermination theory:
“…merely transfers to an invisible region the solution of a problem that
we are trying to solve, at least partially, by investigation of visible
characters; and in the invisible region it is impossible to apply the
methods of science. So, by its very nature, it is barren to investigation,
as there is no means by which investigation may be put to the proof. In
this respect it is like its predecessor, the theory of preformation of the
eighteenth century.” [Hertwig 1900, p. 140]
I hold that all the parts develop in connection with each other, the
development of each part always being dependent upon the
development of the whole.” Furthermore, “during the course of
development, there are forces external to the cells that bid them
assume the individual characters appropriate to their individual
relations to the whole; the determining forces are not within the cells,
as the doctrine of determinants supposed” [Hertwig 1900, pp. 105106, 138].
From our own time
“…successful incorporation of evolutionary principles and theory into
psychological science requires a developmental dynamics perspective.
This perspective recognizes the central role of developmental
processes in all biological and psychological explanations and rejects
the predeterministic and instructionist frameworks common to
contemporary evolutionary psychology and other gene-centered
perspectives on human behavior.” (from Lickliter and Honeycutt, 2003)
The alternative position is gene-centered: “Individual ontogeny is
…understood as the process by which genotypic specification is
translated or expressed into a given phenotype …This view has at its
core a fundamental premise: that the bodily forms, physiological
processes, and behavioral dispositions of organisms can be specified in
advance of the individual organism’s development …”
Tooby and Cosmides (1990):
“Every coherent psychological theory has at its foundation
innate mechanisms or procedures, either explicitly
recognized or tacitly entailed… such procedures are innate
…specified in the organism’s genetic endowment…genetically
based programs regulate the mechanisms governing
development. This genetically specified, innate foundation of
the psyche is the product of evolutionary process, and is the
means by which the evolutionary process organizes the
psychology of the animal over generations.” (p. 22)
A few principles of epigenetics, evo-devo
• Evolution and development are intimately related
• Nothing can be evolved if it cannot be developed
• The targets of selection resulting in major changes in form or behavior are
typically developmental processes
• Conserved genetic processes across extremely wide variety of species, with
relatively small regulatory changes accounting for “endless forms”
• Multilayered interactions from genes through regulatory processes to
external environments and culture, all playing a role in development and
thus in phenotype
• Properties may be self-organized as a result of endogenous activities of the
organism interacting with conditions of the environment—outcomes not
predictable by genes
• Nongenetic factors (gravity, light, temperature, …population density)
change development sometimes dramatically—phenotypic plasticity
(polyphenism)
Bonellia viridis (green spoonworm)
Culture
Culture
Phys./Social
Environment
Behavior
Culture
Phys./Social
Environment
Behavior
Brain/
Body
Cells
Phys./Social
Environment
Behavior
Brain/
Body
Cells
Genes
Culture
Behavior
Brain/
Body
Cells
Genes
Phys./Social
Environment
Brain/
Body
Cells
Genes
Figure 1(after Gottlieb, 2007): Development is the product of bidirectional interactions of multiple
levels (not all levels shown)
Genes
Primary distinguishing characteristics of
our approach to the evolution of language
• Guidance for evolutionary speculation about language
is sought in development
• The earliest vocal developmental patterns
distinguishing humans from other apes are the most
important
• They presumably reflect the earliest changes in
hominin evolution away from the primate background
• The developmental patterns we deem most important
are seen very shortly after birth (and it appears this is
true even in infants born as early as 28 weeks
gestational age)
Age of development
48 mo.
30 mo.
24 mo.
18 mo.
Fig 1: Infrastructural tree
of vocal development
and evolution
7 mo.
Grammaticization
Phonotactic Elaboration
Thematicity
Displacement
Propositionality (Syntax)
Syllable Recombination
Semanticity (True Words)
12 mo.
10 mo.
Metacommunication
Flexible
Prevarication
Conventionality, Arbitrarity
Flexible Triadic Illocution
Adaptable Syllabicity (Designation, Joint Attention)
(Canonical Babbling)
Flexible Imitation
Flexible Directivity, Flexible Interactivity
5 mo.
3 mo.
Vocal Category Development
Functional Flexibility
(Flexible Expressivity)
2 mo.
1 mo.
Infraphonological
domain
Spontaneous Vocalization
(Signal Flexibility)
Comfortable,
Face-to-face
Vocal Interaction
Infrasemiotic
domain
Age of development
Fig 1: Infrastructural tree
of vocal development
and evolution
Flexible Directivity,
Flexible Interactivity
5 mo.
3 mo.
2 mo.
Functional Flexibility
(Flexible Expressivity)
Vocal Category
Development
Face-to-face
Vocal Interaction
Infraphonological
domain
1 mo.
Infrasemiotic
domain
Spontaneous Vocalization
(Signal Flexibility)
Proportion occurrence
of each vocal type
A
1.00
.90
.80
.70
.60
.50
.40
.30
.20
.10
.00
B
Pos
Frequency of
occurrence Neutral
of each
Neg
vocal type
TOTAL
Pos
Neutral
Neg
Cry
Laugh Squeal Vocant Growl TOTAL
2
159
266
926
300
1653
10
10
469
2956
725
4170
278
1
221
511
161
1172
290
170
956
4393
1186
6995
From Oller et al., PNAS, 2013
How could the vocal pattern of
humanity have been selected for?
• We make the evo-devo assumption that small
changes at the genetic (most likely regulatory
level), can result in large changes in vocal
capability
• Epigenetic self-organization
• Selection on spontaneous vocalization
• Self organization of vocal category formation,
and conceivably of functional flexibility
How could selection on spontaneous
vocalization have occurred?
• Altriciality of the hominin infant
• Presumably a product of bipedalism
• Bipedalism may have been a product of aquatic lifestyle
– Wading (Kuliukas, 2009, 2011; Wrangham et al., 2009), diving
(Schagatay, 2011), swimming
– Subcutaneous fat (flotation, insulation) (Hardy, 1960)
– Hairlessness (Morris, 1967)
– Multipyramidal kidney (Williams, 2006)
• And diving could have resulted in voluntary breath control,
presumably creating neural infrastructure of voluntary
vocalization
• But bipedalism seems to have resulted in altriciality in any
case
Selection only on infant capabilities?
• Of course not
• Parental selection in infancy would have initiated
the process of vocal enhancement (Locke, 2006;
Oller and Griebel, 2006)
• Mating pressures could have also selected for
vocalization
• Alliance formation could have been conducted in
part with vocal displays, and thus have supplied
yet another pressure on growth of vocal
capability
– Desmond Morris and Robin Dunbar and the idea of
vocal grooming
Communicative development/evolution: The role of interaction
Production
Signal Function
Recognition
Sender
Reception of
Selection Force
Receiver
Response
Perlocution
S3
S
2
S1
Sn
Sn
S3
S1 S2
Sn
G2
R3
R
R 2
1
……………
Rn
S3
S1 S2
T1
T2
T3
T1
T2
T3
T4
T4
Tn
Tn
…….
S3
S
2
S1
Tn
R3
R
2
R
Rn
…….
T4
G1
1
T1
T2
T3
…….
Ontogenetic increase in volubility
Intergenerational increase in volubility
Sn
Gn
R3
R
R 2
1
Rn