Environment

1
Environment
2
Environment

• Environmental influences relevant to behavior are
  not shared and form part of the non shared
  environment.
• Many environmental measures show a genetic
  influence
• The principle is not about one or the other but
  env-gen interactions, correlations, etc.
• Genetic research provide the best evidence for
  environmental role. (Heritability)
• Environment includes all non-genetic influences
  (congenital and after birth)
• Genetics establishes what is while environment
  predicts what could be

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Environment The nurture assumption by J. Harris

• Environment works in a non-shared manner
• Parenting does not have as much an influence once
  genetics is controlled for
• Peers may play a much more relevant role
• Do they choose their peers based on their genes?

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Environment

• Family resemblance is due to shared genetic
  factors
• Shared family environment plays a very
  insignificant role in psychopathology (except in
  CD and a few others)
• Non-shared environmental influence includes error
  of measurement
• Direct measure of shared environment influence?
  Correlations amongst adoptive siblings (decreases
  with age)
• Differences between MZ twin reared together
  reflect non-shared environment
• This is underestimated due to special shared
  env. and assortative mating

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Nonshared environment

• Studies should assess environmental aspects
  specific to each child
• However even when experiences may be unique to a
  person, it may have been shared by a sibling
• Relevant factors birth order, couples phase,
  peers
• Correlations only up to 0.4
• Are non-shared experiences related to
  psychological outcomes?
• Differential treatment of siblings is influenced
  by their genetic makeup

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Genotype-environment correlations

• Passive Inherited from parents and correlated
  with their genetic propensities
• Evocative How do people evoke reactions given
  their genetic propensities
• Active individuals seeking experiences on the
  basis of their genetic propensities

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Genotype-environment correlations

• Methods of detection
• Passive Compare correlations of environmental
  measures between parents/offspring in adoptive
  and non-adoptive families
• Evocative and active Correlations between
  biological parents traits and adoptive familys
  env. measure
• Multivariate analysis of correlations between
  env. measures and traits