Nature and Nurture

Nature and Nurture

1. Nature - innate influences, characteristics determined by genes. (e.g. secondary sexual characteristics which appear at puberty and conditions like huntingdons disease which are genetically determined.

   • Includes both genetic and evolutionary influences; Schizophrenia has a concordance rate of 40% for MZ twins but 7% for DZ twins which suggests nature is a contributing factors.
   • Plomin et al (1977) - put forward the idea of passive influence (where parents genes determine aspects of their behaviour; so therefore creates a certain type of environment for their children). e.g. if parents are mentally ill it can create an unstable home environment and therefore the child's mental disorder could be the result of indirect influences.
     • Shows how nature can directly influence nurture.

2. Nurture - environmental influences which are determined by interactions with the environment; nurture can affect an infant both before and after birth.

   • Behaviourists suggest that attachment can be explained in terms of classical and operant conditioning; classical conditioning (infant associates mother with food), and operant conditioning (food reducing the discomfort of the hunger).
     • nurture is possible factor in development of attachments.
   • Maguire et al (2000) - the hippocampi of london taxi drivers was bigger than that of non-taxi drivers
     • suggests nurture can directly influence nature.

3. The debate has become meaningless - most psychologists follow an interactionist approach; the disorder phenylketonuria is a genetic disorder but can be prevented from birth if a specialised diet is utilised

   • highlights the importance of taking interactionist approach (e.g diathesis-stress)
     • can be born with a biological vulnerability (e.g. to depression) however the depression will only be triggered by a stressor from the environment.

4. Epigenetics - DNA-histone complex responds to acetylation and methylation, switches genes on and off; life experiences control these switches. explains why identical twins don't look identical.

   • provides support for the fact that genes and environment are much less separate than was thought.