the nature-nurture debate

Question 1

what is the nature-nurture debate?

Answer 1

• it seeks to answer the question of whether our behaviour is more influenced by inherited or acquired characteristics
• it is not really a ‘debate’ as any behaviour / characteristics arises from a combination of both
• for this reason, psychologists are more likely to ask what the relative contribution of each influence is, so it is an interactionist approach

Question 2

what does the diathesis-stress model suggest?

Answer 2

• behaviour is caused by a biological or environmental vulnerability which is only expressed when coupled with a biological or environmental trigger
• eg. person who inherits a genetic vulnerability for OCD may not develop the disorder, but combined with a psychological trigger such as a traumatic experience may result in the disorder appearing

Question 3

what is epigenetics?

Answer 3

it refers to a change in our genetic activity without changing the genes themselves

Question 4

what is epigenetics caused by?

Answer 4

• it is a process that happens throughout life and is caused by interaction with the environment
• aspects of our lifestyle or events we encounter leave marks on our DNA, which switch genes on or off
• this explains why factors such as smoking have a lifelong influence even after you stop
• these epigenetic changes may go on and influence the genetic codes of our children, as well as their children
• epigenetics therefore intriduces a third element to the nature-nurture debate: the life experience of previous generations

Question 5

what does nature refer to?

Answer 5

• inherited influences or heredity
• early nativists such as descartes argued that all human characteristics and some aspects of knowledge are innate
• psychological characteristics like intelligence or personality are determined by biological factors in the same way that physical characteristics like eye colour or height are

Question 6

what does nurture refer to?

Answer 6

• the influence of experience and the environment
• empiricists eg. locke argued that the mind is a blank slate at birth, which is then shaped by the environment
• this view later became an important feature of the behaviourist approach

Question 7

what did lerner (1986) identify?

Answer 7

• different levels of the environment
• this includes prenatal factors, such as how physical influences (smoking) or psychological influences (music) affect a foetus
• more generally, development is influenced postnatally in terms of the social conditions a child grows up in (eg.)

Question 8

how can nature and nurture be measured?

Answer 8

• correlation coefficient: concordance
• such concordance provides an estimate about the extent to which a trait is inherited (heritability)

Question 9

what is heritability?

Answer 9

• the proportion of differences between individuals in a population, with regards to a particular trait that is due to genetic variation
• a figure of 0.01 means genes contribute almost nothing to individual differences and 1.0 means genes are the only reason for individual differences

Question 10

what is the general figure for heritability in IQ? (plomin 1994)

Answer 10

• 0.5 across multiple studies in varying populations
• this means that about half of a person’s intelligence is determined by genetic factors and the other half must be environmental

Question 11

evaluation: use of adoption studies

Answer 11

• they are useful because they separate the competing influences of nature and nurture
• if adopted children are found to be more similar to their adoptive parents, this suggests the environment is the bigger influence and vice verse
• therefore, research can separate the influences of nature and nurture

Question 12

evaluation: adoption and aggression (rhee and walman 2002)

Answer 12

genetic influences account for 41% of the variance in aggression

Question 13

evaluation: research suggests that nature and nurture are not 2 entitities that can simply be pulled apart (plomin 1994)

Answer 13

• people create their own ‘nurture’ by actively selecting environments that are appropriate for their ‘nature’
• this, a naturally aggressive child is likely to feel more comfortable with children who show similar behaviours and will ‘choose’ their environment accordingly
• then, their chosen companions further influence their development
  > plomin refers to this as ‘niche-picking’
• this suggests that it does not make sense to look at evidence as either nature or nurture

Question 14

evaluation: support for epigenetics (susser and lin 1992)

Answer 14

• in 1944, the nazis blocked the distribution of food to the dutch people and 22,000 died of starvation
• S&L (1992) report that women who become pregnant during the famine went on to have low birth weight babies, who were twice as likely to develop schizophrenia when they grew up compared to more typical population rates
• this supports the view that life experiences of previous generations can leave epigenetic ‘markers’ that influence the health of their offspring

Question 15

evlauation: real-world application (nestadt et al. 2010)

Answer 15

• heritability rate at 0.76 for OCD
• such understanding can inform genetic counselling because it is important to understand that high heritability does to mean it is inevitable that the individual will go on to develop the disorder
• this means that people who have a high genetic risk of OCD because of their family background can receive evidence about the likelihood of developing the disorder and how they might prevent this (eg. learn to manage stress)
• this shows that the debate is not just a theoretical one but that it is important, at a practical level, to understand the interaction between nature and nurture

Question 16

evaluation: implications of the debate

Answer 16

• nativists suggest that our genetic make-up determines our characteristics and behaviour, with little environmental input
• this extreme determinist stance has led to controversy, such as linking ethnicity, genetics and intelligence and the application of eugenic policies
• in contrast, but also controversially, empiricists suggest that any behaviour can be changed by altering environmental conditions
• behaviour shaping, a behaviourist concept, has had practical application in therapy
• desirable behaviours are selectively reinforced, and undesirable behaviours are punished or ignored
• carried to an extreme, this could lead to complete social control by the state for the ‘good’ of everyone