Nature – Nurture & the
Brain
Carolyn R. Fallahi, Ph. D.
Principles of Development
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Physical Growth: disproportionate growth
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Proximodistal principle
Cephalocaudal principle
Principle of Hierarchical Integration
Principle of the independence of systems
Brain Development
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Facts about the Brain
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At birth – brain has all the brain cells or
neurons it will ever have.
Regeneration issue.
The role of the environment.
Neural plasticity.
The role of the environment
Dr. Marion Diamond at the U. of California
– Berkley. 1960s.
 How does the brain develop?
 What about IQ?
 PET scans – Positron Emission
Tomography.
 Applications of Brain Research.
 The role of nutrition and the brain.
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Birth to Three – the Brain
100 billion neurons
 1 trillion glial cells
 What happens if there is deprivation or
lack of stimulation?
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Genes and the Brain
100,000 genes in human DNA
 50,000 dedicated to constructing and
maintaining the nervous system
 The role of experience?
 Brandi Binder example.
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Neural Circuitry and Stress
What happens to children who are
physically abused?
 Emotional deprivation?
 Is there critical periods for development?
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Brain Plasticity
B-10
 Age 18
 The potential for greatness is encoded in
the genes; but whether the potential is
realized involves how patterns are etched
by experience in critical years.
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Politics of Biology
Addictive disorders
 Sexual orientation
 Criminality
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Nature or nurture?
The role of genes.
Implications?
1965 study imprisoned criminals
Schizophrenia
LeVay (1991) studies on homosexual males
Genes and Behavior
Are we going to be like our parents?
 Can’t I change my destiny?
 The biology-behavior connection
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Animal Studies
Animal models
Family / adoption studies
Which is stronger? Nature or nurture?
Venter: We simply do not have enough genes
for this idea of biological determinism to be
right. Our environments are critical.
Genes and behavior
Gene expression is vulnerable to
experience.
 Good example…. Fear of snakes.
 What about language?
 Love?
 Antisocial behavior?
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Genes and Behavior
Francis Galton
 John Locke
 Konrad Lorenz
 Ivan Pavlov
 Sigmund Freud
 Noam Chomsky
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Language Development
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Noam Chomsky
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Nature of human language
How do children learn to speak?
Theories prior to 1950
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B. F. Skinner and Behaviorism
Chomsky’s argument
Chomsky’s theory
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The seed language is part of the human
genome.
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Expressed level – surface structure
Deep structure – rooted at the level of the
seed language
How do we convert deep structure into the
surface structure?
Language acquisition device (LAD)