Genes

• Behavioral characteristics inherited from genes.

  As well as physical characteristics we also inherit psychological characteristics.
• Evidence from twin family and adoption services suggest certain behaviors are genetically determined e.g. intelligence
• Heredity plays a huge part, as psychological characteristics are inherited by children from their parents.
• Monozygotic twins are identical with 100% of their DNA whereas dizygotic twins share 50% of their genes and DNA

   
• In psychology tein studies ae used to determine likelihood that certain traits have a genetic basis by comparing the concordance rates between pairs of twins. (extent at which both twins share the same characteristics)

   
• Concordance rate = the likelihood that a trait is present in one person is also found in another. A measure of similarity (usually expressed as a percentage) between two individuals on a given trait.
• If high concordance rate for a certain behavior it may be genetic.

   
• For example, McGuffin et al. (1996) found that if one identical twin has depression there is a 46% chance that the other twin will also have depression.

   
• This suggests there is a genetic component to illnesses such as depression. These relationships are important for understanding the genetic component of psychological illnesses and demonstrate the impact of genes on a certain human conditions
• Genotype: the genetic information / makeup of an individual that is inherited from your parents
• Phenotype: the observable characteristics of an individual. This is the result of the interaction the genotype and the environment.

   
• Genotype + environment = Phenotype