the nature and nurture debate Flashcards
what are the three parts to the nature and nurture debate?
- the interactionist approach
- diathesis-stress model
- epigenetics
what is the interactionist approach
A way to explain the development of behaviour in terms of a range of factors including both biological and psychological ones.
- such factors dont simply add together but combine in a way that cant be predicted by each one separatley.
what is the diathesis-stress model
suggests behaviour is caused by a biological or environmental vulnerability (diathesis) which is only expressed when coupled with a biological or environmental ‘trigger’ (stressor).
what are epigenetics?
- refers to a change in genetic activity without changing the genes themselves.
- happens throughout life
- caused by an interaction with the environment
leave ‘marks’ on DNA which switch on/off e.g. even if you’ve stopped smoking it could still have changed the way your DNA will be expressed. - may go on and change the genetic codes for your children as well as their children - introduces the life experience of previous generations.
what are the key concepts of the nature debate
- inherited influences or hereditary
- psychological characteristics like intellegence/personality are determined by genes, same as physical features like height and eye colour.
what are the strengths to the nature debate
- has helped to identify atypical chromosome patterns as seen in conditions like Klinefelter’s syndrome. Clear indication of a biological basis to scz as condition is not determined by environmental influence. Therefore the nature side of the debate can be evidenced using clinical data.
- The discovery of the nAChR nicotinic receptor in brain is compelling evidence for a pro-nature explanation of nicotine addiction.
what are limitations to the nature debate
- using a purely nature-based approach can result in prejudice, overly deterministic and possibly dangerous assumptions being made about people based on their gender, ethnicity etc. On no emperical basis.
- twin studies have failed to show 100% concordance between MZ twins across a range of studies. McGuffin et al 1996 found that MZ twins showed a 46% concordance rate for depression compared to 20% for DZ twins. Gottesman 1991 found a 48% concordance rate for schizophrenia in MZ twins and 17% concordance rate for DZ twins. As twins share exactly the same DNA the concordance rate should reflect this but bc it doesnt it suggests the environment has a big role to play.
what is the nurture debate
- stresses influence of experience and the environment
- empiricists argue that the mind is a blank slate at birth which means it is shaped by the environment.
what does measuring nature and nurture mean.
- can be represented by a correlation coefficiencey, called concordance
- provides an estimate about the extent to which a trade is inherited.
- 1% means genes contribute almost nothing to individual differences, 100% means genes are the only reason for individual differences.
- general figure for heritability of IQ is 5% across multiple studies in varying populations (Plomin 1994).
- Therefore about 1/2 a persons intellegence is determined by genetic factors and the other half must be environment.
what are the strengths of the nurture approach
- can be clearly seen by the two-process model of phobias. Phobias learnt through classical conditioning. An aversive experience (like being bitten by a dog) changes a neutral stimulus into a conditioned one.
- twin studies - tend to investigate biological nature basis but end up supporting a nurture basis too. Studies fail to find 100% concordance between MZ twins. Suggest that upringing and experience are just as important.
what are the limitations to the nurture approach
- twin studies are still strong indicators that some behaviours may have genetic basis (Nan et al. 2012) found a 61-80% concordance rate for obesity in a sample of 8000 MZ twins.
- the nurture side of the debate cannot account for individual differences within children raised in the same family environment. One child may turn to crime when the other one never breaks the law.
