Genetic Basis

• Psychological characteristics are inherited through genetic instructions.
• Twin studies are used to investigate the genetic basis, analysing the concordance rate of certain behaviours.
• Concordance rate- the extent to which twins share the same characteristics, expressed as a percentage.
• Identical twins- monozygotic (MZ), sharing 100% of genes
• Fraternal twins- dizygotic (DZ), sharing 50% of genes
• Gottesman and Shields:

  • Investigated a genetic component to schizophrenia in twins- natural experiment
  • 62 schizophrenic patients who had a twin from London hospital (1948-1964)
  • MZ concordance= 40%
  • DZ concordance= 7%
  • Therefore there is a genetic predisposition towards schizophrenic which is inheritable, but also environmental triggers to activate the gene
• Genes can form a basis of behaviour, since behaviour and genes are able to be inherited.