3.1.3 Nature vs Nurture

• Nature

  • Advocated by nativists (abilities & skills = native)
  • Descartes = human characteristics are innate and a result of heredity
  • Measured using heritability coefficient
• Heritability coefficient

  • Numerical figure between 0 and 1
  • Measures extent to which characteristic has a genetic basis
  • 1 = entirely genetically determined
• Plomin (1994): Nature

  • Figure for heritability in IQ is about 0.5
  • Implies both environment and genetics are important factors in intelligence
• Topic for Nature

  • Biological explanations for OCD
  • Biological explanations for Aggression
  • Biological explanations for Schizophrenia
• Nurture

  • Advocated by empiricists (Knowledge comes from senses)
  • Locke = mind is a blank slate (tabula rasa); learning is from environment alone
  • Influenced behaviourist approach
• Topics for Nurture

  • Learning theory of Attachment
  • Two-process theory for Phobias
• Relative Importance of heredity and environment

  • Environmental influence begins prenatally and immediately afterwards (eg smoking during pregnancy)
  • Nature & nurture are closely intertwined so it is hard to seperate them
• Twin Studies

  • Provide good argument for nature
  • Difficult to say if high concordance rates are due to shared genetics or the shared upbringing
• Examples of Topics with twin studies

  • OCD
  • Aggression
  • Schizophrenia
• Shared and unshared environments (AO1/AO3)

  • Dunn & Plomin = individual differences mean that siblings may experience different life events (due to age or personality etc)
  • Explains why MZ twins do not show perfect concordance rates
  • Hard to seperate effects of heredity & environment
  • Psychologists consider relative contribution of influences
• Interactionist Approach = N vs N debate considered too simplistic; psychologists have considered ways the two interact
• Interactionist Approach: The diathesis-stress model

  • Predispositional vulnerability is unlocked by environmental stressors
  • Topic Examples: OCD, Schizophrenia, Aggression
• Evidence for Diathesis-stress model: Tienari et al (2004)

  • Finnish Adoption study
  • More likely to have Schz if biological relatives had history of it
  • AND had dysfunctional relationships with their adoptive families
• Epigenetics = the study of how environmental factors can alter gene expression without changing the genetic code; eg smoking, diet , war
• Evidence for Epigenetics: Dias and Ressler (2014)

  • Gave male lab mice electric shocks each time they were exposed to a chemical (acetophenone)
  • Mice showed fear response when scent was present
  • Mice's children also feared the smell even though they had no previous exposure to acetophenone or electric shocks. 
• Evaluation: Contructivism

  • Plomin (1994) - ‘niche picking’
  • Individuals seek their own ‘nurture’ by actively seeking environments (and people) that suit their own ‘nature’. 
  • Therefore, separating the two influences is impossible
• Evaluation: Determinism

  • Taking either a solely nativist or empiricist stance is deterministic and controversial
  • Environmental or Biological determinism
• Evaluation: Causal Relationships

  • Taking a purely nature or nurture stance can be helpful when trying to find cause and effect relationships. 
  • Isolate the effect of N/N
  • Can be used to develop treatment
  • BUT can be used to be applied to eugenics & scientific racism
  • Linking race to genetics & intelligence