nature nurture

• Nature nurture debate


  Arguments considering the extent of the influence of inherited and acquired characteristics on behaviour
• Heredity


  Genetic transfer of mental/physical characteristics from parent to offspring
• Environment


  ANY non-genetic influence on human behaviour

  Ex. pre-natal influences, cultural and social influences, historical influences
• Interactionist approach


  Nature and nurture are so linked that it doesn't make sense to separate them

  - studying the INTERACTIONS of nature and nurture
• Nature


  Nativist beliefs, ex. Descartes

  Human characteristics and SOME knowledge are innate and inherited
• Nurture


  Empiricist beliefs, ex. John Locke

  The mind is a blank slate (tabula rasa) at birth, and experience from the environment.
• Lerner


  Levels of environmental influence:

  Pre-natal (in the womb)

  Social conditions we grow up in

  Historical and cultural contexts
• Plomin


  Heritability coefficient for IQ is 0.5 over multiple studies
• Heritability coefficient


  Assesses heredity

  0 = no inheritance 1 = purely genetic

  - The extent to which a characteristic has a genetic basis
• Twin study problems


  - Are concordance rates from shared genetics or similar upbringing?

  - Nature and nurture are very intertwined
• Diathesis stress model


  - Models of mental illness emphasising the interaction of biological and environmental influences

  - Genetic vulnerability + environmental trigger = condition
• Tienari et al


  Longitudinal finnish adoption study found that children with a high genetic vulnerability to schizophrenia only developed the condition if they were exposed to harsh and critical parenting
• Epigenetics


  - Changes in genetic activity without changing the genome

  - Caused by environmental influences

  - Epigenetic 'markers' are left on DNA and change gene expression

  - Inherited by offspring
• Dias and Ressler


  - Male lab mice given electric shocks when exposed to a acetophenone

  - Both the mice and their offspring feared the smell, even though offspring had not been exposed to acetophenone or shocks before

  - also affected grandchildren
• Implications of nativism


  Nativists = 'anatomy is destiny'

  - Genetic makeup determines behaviour

  = Biological determinism

  - Has been linked to race, sex, etc. in eugenics
• Implications of Empiricism


  Empiricists = behaviour can be altered by changes in the environment = behaviour shaping

  + practical application in therapy, ex. systematic desensitisation

  - manipulative society removing autonomy
• Shared and unshared environments

  - Dunn and Plomin

  - Individual differences causes siblings to experience life events differently, ex. age and temperament

  = This may be why MZ twins never show 100% phenotypic concordance rates
• Constructivism


  - Individuals make their own nurture and environment by choosing environments suitable for their nature

  - Plomin 'niche-picking' and 'niche-building'

  - Children choose their own environments, according to their genes
• Scarr and McCartney


  Three types of genotype-environment interactions

  1) Passive: The parent's genes influence how they treat their children

  2) Evocative: The child's environment is shaped by their genetics

  3) Active: the child chooses their environment based on their genetics

  = complex, multi-faceted relationship