ISSUES AND DEBATES REVISION: NATURE VS NURTURE

NATURE VS NURTURE DEBATE How far are behaviours the product of inherited or acquired characteristics? KEY TERMS: HEREDITY: The GENETIC transmission of physical and mental characteristics from one generation to another ENVIRONMENT: Any influence that is NON GENETIC (for example the environment of the womb, the early childhood experiences, later experiences etc….) INTERACTIVIST: The idea that nature and nurture are linked to such an extent that we cannot separate them, and we should study how they actually interact. KEY POINTS: 1. The debate has a long history: Descartes (17th C) argued that behaviour is result of heredity {Nativist}. Locke (also 17th C) was an empiricist, he argued that we are born a BLANK SLATE. Learning and experience writes on the slate, and our behaviours develop. Everything depends on our environment. This became later known as the BEHAVIOURIST APPROACH. 2. The heritability coefficient is form 0 – 1.0 . It explains how far a behaviour is linked to genetics. For example IQ is around 0.5. This would indicate that both genetics and environment are important. 3. Environmental influences are measured in levels. (Lerner 1986). These may be narrow e.g. Conditions pre-natal, the mothers mood, and physical health, to post-natal cultural and family etc.. are more far reaching 4. It is actually impossible to decide which is more influential because the environment begins to affect us in the womb and after, and even with twin studies these factors cannot be ruled out. So we now tend to think more about INTERACTIVIST approaches and ask which has the BIGGER impact. E.g. The child’s innate temperament effect the way the parents interact with him/her (Nature), but how they interact will affect attachment styles and later behaviour. So there is always interaction. 5. DIATHESIS STRESS MODEL: Most models of MENTAL ILLNESS, emphaisis this interaction. For example SCHIZOPHRENIA. There is genetic influence, but the trigger may be environmental, ie. Family dysfunction (see earlier notes) EVALUATION A03: EPIGENETICS: This refers to a change in genetic activity without changing genetic code. It is caused by interaction with the environment, and happens throughout out life. These leave epigenetic marks on our DNA. This introduces a third element into the debate.. the life experiences of previous generations. / Study with lab mice, giving them electric shocks every time a chemical used in perfume was introduced. They learnt to fear the smell. (Behaviourist) However their children also feared the smell, and their grandchildren. Though they had never been exposed to it before. Extreme Nativism (nature is destiny) has been controversial leading to Eugenics, the desire to control and breed out characteristics based on race and IQ for example. /Also empiricists (blank slate) would suggest that desirable behaviours can be reinforced in therapy. This has also been controversial, for example in Aversion Therapy, for example for homosexuals in 1960.s, or now in some extremist belief systems. There is the issue of Shared and Unshared environments. Individual Differences mean that even siblings raised in the same environment may not have experienced the same upbringing. They may experience a parents divorce differently for example. / This may explain why even MZ twins reared together do not show perfect concordance rates, which supports the view that heredity and environment cannot be separated. CO NSTRUCTIVISM – support for interactivist approach. People create their own ‘nurture’ by seeking out environments that fit with their ‘nature’. So an aggressive child seeks out playmates who have these behaviours. Being around them further affects their development.