Nature VS Nurture

• What does the nature debate argue 


  That behaviours are inherited and are created by our heritage (e.g. genes - these influence hormones and neurotransmitters)
• What did early nativists argue about human characteristics 


  Early nativists were in favour of the nature debate - they argued that human characteristics are innate and the result of our genes
• It is believed that psychological characteristics (e.g. personality or intelligence) are determined by predisposed biological factors, just like physical characteristics are (such as hair colour and eye colour)
• The Nature debate includes:

  • genes - inherited traits and predispositions
  • brain structures and neurochemistry
  • evolutionary influences (e.g. survival and reproduction)
• What methods are used when study nature behaviours

  • brain scanning (fMRI, EEG)
  • Concordence rates as used in twin studies (Cacarro, Carey and Gottesman, Nedtat)
  • DNA analysis via urine or saliva samples (McClintock - pheremones, Dolan - saliva in aggression)
• AO3 (WEAKNESS): NATURE: Biologically Deterministic

  Yerkes believes IQ is an innate and inherited trait. Arguably this then has knock on effects to which school we go to, which university etc.

  This would suggest that many events in our lives are determined and as a result of our biology which would mean that the nature side of the debate is very biologically deterministic and doesn't account for the role of free will.
• Which side of the debate was Bowlby's theory of attachment

  Bowlby's theory of attachment was a pro nature argument as he based his ideas off the work of ethologists such as Lorenz

  • he concluded that attachment is an innate mechanism essential for survival
• AO3 STRENGHT: NATURE: identifies how conditions can be passed

  Understanding genetic inheritance has helped to identify atypical chromosome patterns as seen in conditions such as Kleinfelter's syndrome (extra X chromosome)

  • This is a clear indication of a biological basis of behaviour as the condition which influence how our physical characteristics appear as well as our energy levels, bone density etc

  This provides evidence that features can be inherited and purely due to nature
• AO3: WEAKNESS: Nature: Twin studies fail to show 100% concordence rates

  Carey and Gottesman : MZ = 87% and DZ = 47% in OCD

  McGuffin: MZ = 46% and DZ = 20% in Depression

  Cacarro: Verbal: MZ = 50%, DZ = 19%, Direct: MZ = 28%, DZ = 7% in aggression

  As MZ twins share 100% of DNA and DZ share 50% you'd expect concordance rates to reflect this, however they don't which suggests there must be other factors that determine behaviours outside of nature/inheritence

  • this giver rise to an interactionist model between features of nature and nurture
• What does the nurture debate argue

  Behaviour is created through the environment and environmental learning
• What do extreme nurture empiricists such as Locke argue 


  Extreme nurture empiricists such as Locke argue that the mind is a blank slate at birth and it is shaped by interaction with the environment (e.g. the behaviourist approach)
• What are the different levels of the environment that Lerner (1986) identified


  Prenatal Terms: e.g. the mother smoking or hearing music

  Postnatal Terms: e.g. the social/environmental conditions that a child grows up in
• The nurture debate includes:

  • Learning (classical/operant conditioning)
  • Socialization (family, peers, culture)
  • Life events (trauma, education)
• Relevant Research to the nurture debate

  • classical and operant conditioning (behaviourism)
  • conformity to social roles (Stanford prison - social influence)

  Learning theory of attachment: Dollard and miller - cupboard love theory

  • assumes babies attach to whoever feeds them
  • the person who feeds them changes from the NS to the CS as thy become associated with food which is the UCS
• What is an interactionist approach

  An approach that combines both nature and nurture to describe behaviours

  (in other words, nature and nurture interact)

  FOR EXAMPLE: attachment can be explained by either:

  • parental love (NURTURE) - Bowlby's maternal deprivation theory
  • child's temperament (NATURE) - Kagan's temprament hypothesis

  This shows how conflicting evidence could suggest that environment and heritage interact
• What is a diathesis stress model

  This explains how a genetic predisposition/vulnerability (diathesis) is triggered by an external trigger (stressor)

  FOR EXAMPLE:

  Frazetto (MAOA gene and aggression): showed that people can have a low variant MAOA gene without being aggressive, but those who had the low variant MAOA gene alonside trauma in early life were the ones who were aggressive
• WHat are epigenetics

  A genetic predisposition which can be moderated or switched on by the environment

  • epigenetics is a change in genetic activity (doesn't alter DNA) but encourages or supresses certain genes from being expressed.
• What can turn genes on or off (epigenetics)


  Lifestyle and events we encounter (e.g. smoking, diet or trauma) can lead to marks on our DNA and switch them on of off,

  FOR EXAMPLE

  You may have the genes to grow to 6'0 but you ate really poorly as a child so your environment capped you at 5'8.
• RESEARCH ON EPIGENETICS: Tobi et al

  Tobi et al found epigenetic changes were brought about by starvation during pregnancy.

  • This led to a change in the expression of genes coding for fat storage in the developing foetus
• AO3 (STRENGTH): Nurture: Evidence through models

  The nurture argument is supported by the two process model of phobias (phobias occur due to classical conditioning and are maintained through negative reinforcement through Operant Conditioning)

  • This provides empirical and well-studied evidence that nature plays a role in developing certain disorders such as OCD
  • Therefore it is valid
• AO3: STRENGTH: Nurture: Twin studies fail to show 100% concordence rates

  Carey and Gottesman : MZ = 87% and DZ = 47% in OCD

  McGuffin: MZ = 46% and DZ = 20% in Depression

  Cacarro: Verbal: MZ = 50%, DZ = 19%, Direct: MZ = 28%, DZ = 7% in aggression

  As MZ twins share 100% of DNA and DZ share 50% you'd expect concordance rates to reflect this, however they don't which suggests there must be other factors that determine behaviours outside of nature/inheritance

  • this giver rise to an interactionist model between features of nature and nurture
• Nature

  Biologically reductionist
• Nurture

  Environmentally reductionist