Key Assumptions

• The biological approach assumes all psychological behaviours/functions have a biological root at their core
• Genetics

  The role of inherited traits in behaviour
• Neurotransmitters

  The role of serotonin in behaviour
• Hormones

  The role of testosterone in behaviour
• Brain Structures

  The role of the hippocampus in behaviour
• A genetic explanation of behaviour is that genes influence all traits, characteristics and behaviours e.g. intelligence is inherited in the same way as height and other physical characteristics
• Twin studies are used to investigate a genetic basis for specific traits e.g. IQ, criminality, schizophrenia

  Monozygotic (MZ) twins are compared to Dizygotic (DZ) twins

  Concordance rates are used to measure the rates of agreement in a twin study. A high concordance rate indicated evidence of a causal connection between the twin type and the trait/behaviour
• If a characteristic is genetic, it would be expected for MZ twins to have a 100% concordance rate and DZ would be 50%.
• Genotype - A persons particular set of genes that make up their DNA, made up of a combination of alleles that compromise a specific gene
• Phenotype - The expression of the genotype determined by prevailing external influences and comprises and individuals observable traits

  e.g. Height, eye colour, hair texture
• High Phenotypic Plasticity - The environment has a large effect on the observable characteristic/trait (Phenotype)

  Low Phenotypic Plasticity - The environment has little effect on the observable characteristics, e.g. eye colour, blood type
• Evolution

  Looks at why and how specific human traits have evolved via the process of natural selection, e.g. aggression, memory, language