Nature-Nurture Flashcards
Nature vs Nurture
This debate looks to the extent to which our behaviour is influenced by nature (genes) or nurture (environment). It is presented as a dichotomy, can only be one or the other.
Nature (Inherited Influences)
1) Nativists (Descartes) believed we are born with innate characteristics.
2) Behaviour is determined by biological factors (deterministic view).
3) Genes provide blueprint for all behaviours.
Nurture
1) Empiricists (Locke) argued the mind is a ‘blank slate’ at birth & is shaped by interactions with the environment (e.g. behaviourist approach).
2) Your limits depend on quality of external influences & not genes.
Research Support - Nurture
Classical Conditioning of Fear (Little Albert)
Before Study - No fear of white rat.
During - Rat & loud noise paired.
Fear transferred to similar objects & a month later the fear stayed.
Conclusion - conditioning of fear was evident, provides evidence that the environment can be manipulated to create a change in behaviour.
Reaction Range
1) Certain characteristics e.g. height, weight & intelligence have a reaction range.
2) Everyone has a genetic potential (genotype) for these characteristics.
But it is the environment that will determine to what extent the genotypic potential will be achieved.
E.g. Height
A person could have genes that will make them tall. But if they are raised in a household where there is poor nutrition, they may not end up as tall.
–> So both nature and nurture have an effect.
Interactionist Approach
1) Nature & Nurture interact to form human personality.
E.g. attachment can be explained in terms of quality of parental love or child’s temperament.
Diathesis-Stress Model
1) Behaviour is caused by a genetic vulnerability (diathesis) which is only expressed when coupled with environmental triggers (stressor).
E.g. Someone has a genetic predisposition to SZ but it might take an environmental cue to trigger the disorder.
Epigenetics
1) A change in genetic activity without changing the genetic code.
2) Lifestyle & events we encounter leave ‘marks’ on our DNA - switching genes on/off –> has a lifetime influence & can be passed to future gens.
Measuring Nature & Nurture
1) Concordance - degree to which 2 ppl are similar on a particular trait.
2) Heritability - proportion of differences between individuals in a population, with regards to a particular trait, due to genes.
0.01 is very little - 1 means genes are the only reason.
E.g. figure for heritability in IQ is 0.5.
Twin Studies
(research support)
1) MZ twins share 100% of genes, DZ share 50% on average –> so we would expect a greater likelihood of both MZ twins developing same behaviour if it mostly genetic.
2) Since MZ & DZ twins are raised in same environment but MZ twins have a greater degree of genetic similarity.
3) Twins are useful in studying nature/nurture as researchers can identify behaviours/traits that are due to genetic influence more explicitly.
E.g. Holland et al. (1988) surveyed anorexia rates. MZ had 56% concordance rates & only a 5% concordance rate amongst DZ.
This showed that anorexia has a genetic component.
–> Wasn’t 100% CR so there must be some environmental influence.
It could be that MZ are treated more similarly.
Adoption Studies
(research support)
1) Adopted children are compared to their biological parents and to their adoptive parents.
2) Researchers can determine which traits are of genetic influence (nature/biological) and which are of environmental influence (nurture).
E.g. Plomin et at. (1988) found there was a stronger correlation of IQ with biological families than with adoptive families.
–> So it is possible to argue that nature is more important than nurture in the development of intelligence.
Strength of Debate
RESEARCH SUPPORT FOR EPIGENETICS:
1) Research found women who became pregnant during the Dutch Hunger Winter famine had low birth weight babies who were twice as likely to develop schizophrenia.
–> Suggest life experiences of previous gens can leave epigenetic ‘markers’ that influence health of offsprings.
Strength of Debate
REAL-WORLD APPLICATION:
1) Heritability for OCD was put at 0.76 - highly heritable which can inform genetic counselling.
2) Ppl with high risk of OCD cause of family bg can receive education about the disorder –> Shows the debate is important at a practical level & not just theoretical.
