The Biological Approach

• State the assumptions of the biological approach:

  • Everything psychological is at first biological, so to fully understand human behaviour, we must look to biological structures and processes within the body, such as genes, neurochemistry, the nervous system
  • An understanding of brain structure and function can explain our thoughts and behaviour
  • From a biological perspective, the mind lives in the brain - meaning that all thoughts, feelings and behaviour ultimately have a physical basis
• Key concepts of the approach - the influence of genes on behaviour

  • What are genes?

  They make up chromosomes and consist of DNA which codes the physical features of an organism (such as hair colour, height) and psychological features (intelligence) genes are transmitted from parents to offspring
• What are monozygotic (MZ) twins?

  Identical twins - found to have higher concordance (agreement or consistency) rates. They share 100% of the same genetic material.
• What are dizygotic (DZ) twins?

  Non-identical twins. They only share 50% of the same genetic material.
• Explain why twin studies are used to explore the role of genetics?

  Twin studies are used to determine the likelihood that certain traits have genetic basis by comparing the concordance rates between pairs of twins, that is to the extent that they share the same characteristic
• When can we suggest that 'there is a genetic basis' for a particular characteristic?

  If monozygotic twins are found to have higher concordance rates than non-identical (dizygotic) twins - for musical ability, schizophrenia, love of romance films etc. it would suggest genetic basis
• What are the issues with using twin studies?

  Twins may not represent the general population. The unique circumstances of being a twin (i.e. sharing a womb, growing up with twins may result in different developmental experiences, which might not occur for non-twins)
• What is a genotype?

  Actual genetic makeup - particular set of genes a person possesses. Everyone (except identical twins) has their own unique genotype.
• What is a phenotype?

  The way genes are expressed through physical, behavioural and psychological characteristics
• What is evolution?

  The changes in inherited characteristics in a biological population over successive generations
• What is natural selection?

  Any genetically determined behaviour that enhances an individual's survival will continue in future generations i.e. be naturally selected
• Jennifer and Jessica Gadirova are identical twins and were both selected for the Great Britain gymnastics squad and competed at the Tokyo 2021 olympics

  • Nature explanation (biological): They share the same genes which makes them win
  • Nurture explanation (environmental): They trained in the same way
• What are concordance rates?

  A percentage rate from 0-100 that describes how similar two people are.
• More information about the genotype?

  The expression of a genotype is influenced by environmental factors. Much of human behaviour depends on an interaction between inherited factors (nature) and the environment (nurture).
• Why may identical twins look different?

  Due to their different phenotypes. One may exercise more and have a healthier diet. So despite them having the same genes, the way the identical twin genes are expressed (the phenotype) is different.