Transcript JaredS - ShinyVerse

Simulated Evolution of Language
By: Jared Shane
I400: Artificial Life as an approach to Artificial Intelligence
January 29, 2007
Introduction
• What evolutionary forces propelled the
development of language?
• Are the language abilities of humans the
result of a language-specific portion of the
brain or do they result from a general
application of our cognitive abilities?
Introduction (cont.)
- These questions are the oldest and most
difficult to answer.
• Only within the last century that the
sciences of evolutionary biology,
computation, psychology, and cognitive
sciences have been able to provide direction
and focus in search for answers
Theories of Language Evolution
• What is the heart of human uniqueness?
– Characteristics that separate humans from
animals.
– One of the most important factors separating
humans from animals is the use of language
– Humans have exceptional language skills
relative to animals, as well as more powerful
intellectual skills
The Birth of Language
• The controversy and the approach started by
Noam Chomsky in the middle of the 20th
century
– He published his ideas regarding the biological
basis of language
• Since then, most history has been a response to him
• Two views taken
• Nativist vs. Non-nativist
The Nativist View
• The pure nativist believes that language
ability is deeply rooted from in the biology
of the brain.
– They claim our ability to use grammar and
syntax is an instinct, or dependent on specific
modules of the brain, or both.
The Nativist View (cont.)
• Reasons for believing the nativist view:
– Genetic/biological data
– Research in child acquisition
• Nativists claim that there are many mistakes
that children do not make
• They claim children are able to learn
language fluently if they are exposed to it
before age 6
The Non-Nativisit View
• Children learn through the properties of
their parents speech
• Words and phrases used most commonly by
parents will be first words, phrases, and
even grammatically structures learned by
children
• Much evidence supporting the non-nativist
view is evidence against the nativist view
The Non-Nativisit View (cont.)
• Evidence indicates children pay more attention
to some words than others
• Only after children generalize verbs to a variety of
contexts and forms do they begin to acquire verbs
• The final argument for the non-nativist is the best
theory is usually the one that incorporates the
fewest unnecessary assumptions
The Evolution of Language
• Any scientist hoping to explain language evolution
needs to explain two things:
– The first usage of words as symbols
• “Evolution of Communication”
– The first usage of what we might call grammar
• “Evolution of Syntax”
• Three dominant theories of language evolution
– Bickerton: Incorporating the fossil record
– Pinker and Bloom: On Natural Selection
– Deacon: The Natural Selection of Language Itself
Bickerton: Incorporating the
fossil record
• 1990, Derek Bickerton authored a theory based on
the notion of Primary Representation System
(PRS)
– The way in which humans represent the world forms
the basis for the structure of human language, which
evolved in stages
• He proposed that the PRS of humans is
fundamentally binary and hierarchical
– The concept in our minds that seem to correspond to
notions in the world are defined horizontally as well as
vertically
Bickerton (cont.)
• Another reason for believing full language did not
exist until recent:
– There is little evidence in the fossil record prior to the
beginning of the Upper Paleolithic (1000,000- 40,000
years ago)
• One drawback to Bickerton’s theory:
– The problem with an explanation relying on a
sudden genetic mutation is that on many levels it is
no explanation at all.
– It takes an unsolved problem in linguistics and
answers it by moving it to an unsolved problem in
biology
Pinker and Bloom: On Natural
Selection
• In 1990, Pinker and Bloom argued that human
language capacities must be attributed to
biological natural selection based on two
criteria:
– Complex design
– Complexity is a characteristic of all human languages
– The absence of alternative processes capable of
explaining such complexity
– Demonstrates that there are no processes other than
biological natural selection that can explain the complexity
of natural languages
Pinker and Bloom (cont.)
• Evidence seems to argue that the language must be
the product of biological natural selection, but
there are drawbacks.
– They do not suggest a plausible link between their ideas
and what we currently know about human evolution
– They never put forth a believable explanation of how an
additional mutation in the form of one more grammar
rule would give an individual selection advantage
– These arguments are vulnerable in some areas to
counter-arguments based primarily on the notion of that
general intelligence may be the key to our language
understanding
Deacon: The Natural Selection of
Language Itself
• One of the arguments to the viewpoint that
language is the product of biologically-based
natural selection is the idea that rather than the
brain adapting over time, language itself adapted
• This view is not vulnerable to many of the basic
problems with other views
– It's difficult to account for the relatively rapid rise of
language ability reflected in the fossil record with an
account of biologically based evolution
• Another powerful and attractive aspect of
Deacon’s theory is its simplicity
– It acknowledges that there can be linguistic universals
Questions and/or Comments??
Thank You!
Reference Information
Amy Perfors. “”Journal of Artificial Societies
and Social Simulation.” Simulated
Evolution of Language: a Review of the
Field. 31 March 2002. 23 January 2007.
http://jasss.soc.surrey.ac.uk/5/2/4.html