Nature-nurture debate

Nature

• Early nativists believed that human charcteristics and even some knowledge is innate, the result of heredity
• The heritability coefficient is used to assess heredity (0-1), this indicates the extent to which a charcteristic has a genetic basis (1=entirely genetically determined)
• General heritability coefficient for IQ is 0.5, suggests that intelligence is influenced by both genetics and environment

Nurture

• Early empiricists argued that the mind is a blank slate at birth (tabula rasa), learning and experience is written on it
• The importance of environmental influences on beh became a key feature of the behaviourist approach
• The 'environment' is a broad and complex concept: Lerner identified different levels of environmental influences, including pre-natal factors and post-natal experiences

The relative importance of heredity and environment

• Nature and nurture are so closely intertwined that it is difficult to separate them
• E.g. in twin studies, it is very difficult to establish whether a high concordance rate for a particular beh is the result of shared genetics or shared upbringing 
• Because of this, most of the focus now is not trying to establish which one affects beh but rather the relative contribution of each influence on human beh

The interactionist approach

• E.g. The Diathesis-stress model of mental illness…