nature- nurture debate Flashcards
Interactionist approach?
It is not really a debate because all characteristics combine nature and nurture (even eye colour is only .80 heritable). For example attachment can be explained in terms of quality of parental love (Bowlby 1958) or child’s temperament (Kagen 1984). Environment and heredity interact.
Diathesis-stress model?
Behaviour is caused by a biological/environmental vulnerability (diathesis) which is only expressed when coupled with a biological/environmental trigger (stressor). For example, a person who inherits a genetic vulnerability for OCD may not develop the disorder. But, combined with a psychological trigger (traumatic experience) this may result in the disorder appearing.
Epigenetics?
This is a change in genetic activity without changing the genetic code. Lifestyle and events we encounter (e.g. smoking, diet, trauma, war) leave marks on our DNA (genes) - switching genes on or off. This has a lifelong influence and can be passed onto future generations.
Nature?
Early nativists (e.g. Descartes, 17th century) argued that human characteristics are innate - the result of our genes. Psychological characteristics (e.g. intelligence or personality) are determined by biological factors, just like eye colour or height.
Nurture?
Empiricists (e.g. Locke, 17th century) argued the mind is a blank slate at birth, and is shaped by interaction with the environment e.g. the behaviourist approach. Lerner (1986) identified different levels of the environment:
Prenatal terms e.g. mother smoking or hearing music
Postnatal experiences e.g. the social conditions a child grows up in
How to measure nature and nurture?
Concordance is the degree to which two people are similar on a particular trait. Heritability is the proportion of differences between individuals in a population, with regards to a particular trait, due to genes. 0.01 (1%) is very little contribution, 1.0 (100%) means genes are the only reason. The figure of heritability in IQ is about 0.5 (Plomin 1994).
A03: One strength of the nature-nurture debate is support for epigenetics.
In 1944, the Nazis blocked the distribution of food to the Dutch people and 22,000 died of starvation (the Dutch Hunger Winter). Susser and Lin (1992) found that women who became pregnant during the famine had low birth weight babies who were twice as likely to develop schizophrenia.
This suggests that the life experiences of previous generations can leave epigenetic markers that influence the health of their offspring.
A03: Another strength is the debate can have real world application.
Nestadt et al (2010) put the heritability rate at .76 for OCD i.e. it is highly heritable. Such understanding can inform genetic counselling. People who have a high genetic risk of OCD because of their family background can receive education about inheritance, management and prevention of the disorder.
This shows that the debate is not just theoretical but that it is also important, at a practical level, to understand the interaction between nature and nurture.
A03: A further strength in nature-nurture research is adoption studies.
If adopted children are more similar to their adoptive parents, suggests environmental influence, if more similar to biological parents, suggests genetic influence. Rhee and Waldman (2002) found in a meta-analysis of adoption studies that genetic influences accounted for 41% of variance in aggression.
This shows how research can separate nature and nurture influences
A03 (counter): However research suggests that this approach may be misguided, that nature and nature and not two entities that can simply be pulled apart.
Children create their own nurture by selecting environments appropriate to their nature - a naturally aggressive child will choose aggressive friends and become more aggressive (niche-picking, Plomin).
This suggests that it does not make sense to look at evidence of either nature or nurture.
