Evolution, Genes, and Behaviour

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Evolution, Genes, and Behaviour
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Nature versus Nurture

• Traditionally an either/or argument
• What is the source of the nature in human
  nature?
• Nativism genetic determinism
• Innate, inborn
• Empiricism environmental determinism
• Blank slate, learning

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Nature versus Nurture

• Geniuses and idiots are born, not made
• Vs
• Everyone is born with the same potential

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Nature and Nurture

• Today, more focus on interaction of nature and
  nurture to explain human nature
• Genelt-gtEnvironment Interactions
• Epigenetics
• On or over the genetic information encoded in
  the DNA
• "Epigenetic regulation of the glucocorticoid
  receptor in human brain associates with childhood
  abuse."
• Nature Neuroscience, 2009

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Nature and Nurture

• complex contributions of both and how each affect
  the other/relative importance of each factor with
  respect to different traits

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Nature and Nurture

• Behavioural Genetics
• Differences (individual variation)
• identical twins raised together or apart
• Adoptees
• Heredity deals the cards environment plays the
  hand.
• Psychologist Charles L. Brewer
• (1990)

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Nature and Nurture

• Evolutionary Psychology
• Commonalities (human universals)
• Evolutionary Biology Cognitive Psychology
• Goal is to understand the human mind/brain from
  an evolutionary perspective
• The design of the mind must have been shaped by
  natural selection (including sexual selection)

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Evolutionary Psychology

• Source of psychological mechanisms

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Evolutionary Psychology

• Evolutionary psychologists propose that humans
  evolved tendencies to think, feel, and behave in
  certain ways, and not others because...
• In a word Adaptations

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Evolutionary Psychology

• Our mental lives and behavior reflect the
  evolutionary history of our species, particularly
  the adaptive problems that had to be solved

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Evolutionary Psychology

• Adaptive Problems
• avoiding predators
• eating the right food
• attracting mates
• forming alliances
• reading others peoples minds

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Evolutionary Psychology

• Human brain contains neural circuits designed by
  natural selection to solve problems that our
  ancestors had to overcome in our evolutionary
  history
• The human mind consists
  of a set of
  domain-specific
  information processing
  modules

Inputs
Decision Rules
Outputs
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Evolutionary Psychology

• Evolutionary
  psychologists argue
  that there are
  very
  many (hundreds?
  thousands?) of
  specialised
  modules in
  the human mind

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Evolutionary Psychology

• Ex. Paternal love
• Obligatory parental investment
• genes for fathering motivation became standard
  equipment in the genetic complement of human
  males, just like genes code for facial hair in
  males
• Still, there is variation across males
  (behavioural genetics)

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Evolutionary Psychology

• Evolutionary adaptations are general and flexible
• e.g., we have not evolved to understand specific
  languages, such as French or English, but rather

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Evolutionary Psychology

• Not all human abilities evolved via natural
  selection
• your ability to read
• 3 characteristics of evolved adaptations
• adaptive, heritable, and universal

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Human Evolution

• innate human characteristics
• Attraction to novelty
• Desire to explore
• baby math
• butmany aspects of
  human behaviour that
  
  probably reflect evolutionary
  adaptations but do not
  increase survival
  and
  reproduction in contemporary
  environments

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Human Evolution

• infant reflexes
• Some are evolutionary
  carry-overs
• No longer have any apparent survival value
• Swimming reflex
• Moro reflex
• Babinski

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Human Evolution

• fats and sugars - evolved tastes
• Backfires in contemporary environments

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Human Evolution

• fats and sugars - evolved tastes
• Backfires in contemporary environments

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Mismatch Theory
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Mismatch Theory

• Have to consider the environment of evolutionary
  adaptedness (EEA) - environments in which a
  species evolutionary adaptations were selected
• in which our ancestors lived for millions of
  years prior to the rise of agriculture
• The Pleistocene period 2 million 10,000 years
  ago

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Mismatch Theory

• Compare this with modern environments to explain
  maladaptive behaviour today
• Modern human brain consists of modules from the
  past

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Mismatch Theory
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Darwins theory of evolution by natural selection

• 3 major principles
• heredity
• characteristics are passed from one generation to
  the next
• variability
• characteristics vary across members of a species
• some individuals will be more successful in their
  environment than others
• demand for resources produces selective pressure

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Darwins theory of evolution by natural selection

• 3 major principles
• natural selection (survival of the fittest)
• how species change, or evolve, over time
• only those members of a species able to compete
  successfully for limited resources will survive
  and reproduce

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Darwins theory of evolution by natural selection

• ButDarwin had a problem