AO1

• The biological approach focuses on the importance of physical processes, such as genes and neural function.
• There are four key aspects of the biological approach:

  • Neurochemical basis of behaviour
  • Genetic basis of behaviour
  • Genotype and phenotype
  • Evolution and behaviour
• Neurochemical Basis of Behaviour


  Neurochemistry is the actions of chemicals and behaviour. Thoughts and behaviour are reliant on neurochemistry, which occurs using neurotransmitters. An imbalance of neurochemicals may explain some mental illness. For example, OCD may be due to low serotonin.
• Genetic Basis of Behaviour


  Some psychological traits, such as intelligence, are inherited. This is tested through twin studies by analysing concordance rates (the rate of which genes are the same). If a characteristic is genetic, we can accept that all identical twins are concordant, sharing 100% of the same genes. However, non-identical twins share 50% of the same genes.
• Genotype and Phenotype


  Genotype is the genetic makeup and phenotype is the way genes are expressed through physical, behavioural and psychological characteristics. Even though twins share the same genes, their phenotype is different. This shows that human behaviour is not solely influenced by genes, nature, but also by environment, nurture.
• Evolution and Behaviour


  Darwin proposed the theory of natural selection, which suggests that any genetically determined behaviour that enhances survival will be naturally selected to continue through generations. This occurs because certain traits provide advantages and the person who has it is more likely to survive, reproduce and pass down the trait.
• Evolution and Behaviour: Criticism

  Some critics such as Popper say that it is impossible to prove natural selection as we cannot see it happening and can only assume it has taken place. However, some say that the basic principles of this theory as supported by fossil records, such as dinosaurs changing into birds.