the nature-nurture debate

Question 1

the interactionist approach

Answer 1

• the NN debate seeks to find whether behaviour is more influenced by nature or nurture
• not really a debate as any characteristic arises from both
• historically, we thought nature and nurture worked in isolation
• for example, Bowlby claimed that attachment type is determined by warmth and continuity of parental love, whereas Kagan proposed that innate personality also affects attachment (environment and heredity interact)
• debate is really about how nature and nurture interact (interactionist)
• constructivist approach (nature creates nurture)

Question 2

diathesis-stress model

Answer 2

• suggests behaviour is caused by biological or environmental vulnerability, which is only expressed when coupled with a biological or environmental trigger (stressor)
• diathesis is biological component
• for example, someone who inherits a genetic vulnerability for OCD may not develop the disorder, but when coupled with a psychological trigger, the disorder may appear
• diathesis does not have to be a genetic basis, could be caused by severe trauma in childhood which would affect the developing brain

Question 3

epigenetics

Answer 3

• a change in our genetic activity without changing the genes themselves
• happens throughout life and is caused by interactions with the environment
• aspects of our lifestyle or events we encounter (such as smoking or trauma) leave marks on our DNA, which switch genes on or off
• explains why factors such as smoking have a lifelong influence even after you stop, they have changed the ways your genes are expressed
• these epigenetic changes may go on and influence the genetic codes of our children, as well as their children (transgenerational process)
• therefore introduces a third factor into the NN debate - the life experience of previous generations
• interactionist approach, environment influencing how dna works

Question 4

constructivism

Answer 4

• we construct our environment based on nurture
• people select, modify and create environments correlated with genetic disposition
• what appears to be an environmental influence (nurture) may actually be a genetic influence (nature)
• for example, a child who is genetically predisposed to be a competent reader is likely to seek out opportunities to practice this and reinforce this because it is rewarding
• innate tendencies drive us to do a certain behaviour
• the MAOA gene is linked with violence, these people might seek out people and environments that reward this (eg. sports such as rugby)

Question 5

key concepts - nature

Answer 5

• refers to inherited factors, or heredity
• nativists such as Rene Descartes argued that all aspects of human behaviour are innate
• physical and behavioural characteristics that are displayed (phenotype) are inherited in the human genome (genotype)
• influenced by chemicals such as hormones and neurotransmitters

Question 6

key concepts - nurture

Answer 6

• refers to the influence of experience and the environment
• interactions with the environment
• empiricists such as John Locke argued that the mind is a blank slate at birth which is then shaped by the environment (important feature of behaviourist approach)
• Richard Lerner identified different levels of the environment, including prenatal factors such as how physical or psychological influences affect the foetus

Question 7

key concepts - measuring nature and nurture

Answer 7

• the degree to which two people are similar on a particular trait can be represented by a correlation coefficient (concordance)
• this provides an estimate to the extent at which the trait is inherited (heritability)
• this is the proportion of differences between individuals in a population that is due to genetic variation

Question 8

evaluation - adoption studies

Answer 8

• adoption studies 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 has bigger influence
• if adopted children are found to be more similar to their biological parents, this suggests that genetic factors have bigger influence
• a meta-analysis by Rhee and Walkman found that genetic influences account for 41% of the variance in aggression

Question 9

evaluation - epigenetics

Answer 9

• an example of how environmental effects can span generations through epigenetic effects comes from the second world war
• the nazis blocked the distribution of food to the dutch, Susser and Lin found that women who became pregnant during this famine went on to have low birth weight babies
• these babies were twice as likely to develop schizophrenia when they grew up
• supports that life experiences of past generations can leave epigenetic markers that influence offspring
• also support from Dias and Ressler who gave electric shocks to male rats when they smelt acetophenone, showed fear response and so did children and subsequent children

Question 10

evaluation - real-world application

Answer 10

• research shows that OCD is a highly heritable mental disorder
• this understanding can inform genetic counselling, high heritability doesn’t mean it is inevitable that the individual will develop the disorder
• people who have a high genetic risk of OCD can receive advice about the likelihood of developing the disorder and how they may prevent this
• debate is also important at a practical level

Question 11

evaluation - twin studies

Answer 11

• nestadt study on ocd
• concordance rates were 68% for mz and 31% for dz, higher for mz so supports nature
• if it was just nature, rates would be 100% for mz so there must be some influence from environment too, refutes nature
• the 32% of mz who didnt develop ocd perhaps had different life experiences and were not exposed to the trigger (diathesis-stress model)

Question 12

evaluation - epigenetic determinism

Answer 12

• hard determinism
• not much free will, choice of environment based off of innate tendencies
• biological determinism, we have no control over genetic makeup
• environmental determinism, we have no control over the influences of our parents and grandparents

Question 13

evaluation - being able to isolate nature / nurture

Answer 13

• we can develop treatments / interventions / preventions to help people and society
• for example, nature and understanding the involvement of serotonin in OCD, development of SSRIs
• for example, nurture and understanding conditioning in aquisition of phobias, development of treatments like SD and flooding
• identification of candidate genes, genetic counselling to help people understand their level of risk and to be aware of how to prevent the certain behaviour being triggered