Biological Approach

• Identify three basic assumptions of the biological approach.


  Behaviour has evolved through natural selection whereby profitable behaviours that aided survival have been reproduced.

  Behaviour has a genetic basis though environment can also play a role as seen in phenotypes (observable characteristics that result from the combined effect of genetics and the environment.

  Biological structures (e.g. the brain) and neurochemistry (e.g. hormones and neurotransmitters) influence behaviour.
• Explain the role of evolution on behaviour.


  Behaviours have evolved due to natural selection.

  This means that profitable behaviours that aided survival were chosen in mates and reproduced.
• Evaluate the role of evolution on behaviour.


  There are alternative theories as to why some ‘evolutionary advantageous’ behaviours are displayed E.g. behaviourists have proposed that an infant may attach to their caregiver because they learn to associate them with food. Meanwhile, a phobia of snakes may develop if an individual learns to associate snakes with the act of being bitten. This is a limitation because it suggests that some behaviours that are thought to have evolved have

  actually been learned through environmental experiences during the individual’s existence.
• Distinguish between genotype and

  phenotype.


  Genotype = the genetic makeup of an individual.

  Phenotype = the characteristics of an individual that are affected by their genes and environment. This means that although MZ twins share the same genes, they may show different

  characteristics (e.g. one more social than the other) due to environmental influences (e.g. one being bullied).
• Outline the genetic basis of behaviour.


  Biological psychologists propose that there is a genetic basis to behaviour in that the genes an individual possesses play a significant role in their behaviour.

  This means that biological psychologists have studied genotypes (individuals’ genetic make-ups) and phenotypes (an individual’s characteristics that are the result of their genes and environment).
• Evaluate the genetic basis of behaviour.


  Higher concordance rates in MZ twins than DZ twins could be affected by a confounding variable. E.g. MZ twins are always of the same sex, which may not be the case for DZ twins, and so are likely to have the same friendship groups. This is a limitation because the higher concordance rates in MZ twins than DZ twins may be due to their more similar environmental experiences rather than their more similar genetics. Therefore questions credibility.
• Evaluate the genetic basis of behaviour.


  Adoption studies have further supported the proposal that there is a genetic basis to behaviour. E.g. adoption studies have found that an adopted child is at an increased likelihood of developing disorders such as schizophrenia if their biological parent was diagnosed with schizophrenia. If environment was the sole cause then the child would not be at an increased likelihood, unless their adoptive parent had the disorder.
• Evaluate the genetic basis of behaviour.


  Adoption studies also have methodological flaws. E.g. most adopted children studied had spent some significant time with their biological parents before being adopted. Also, the children are typically adopted into families that are similar to their biological family. This is a limitation because if an adopted child is at an increased likelihood of displaying a behaviour/disorder if their biological parent also displays it, it may be that they learned that behaviour while with them or that their adoptive family also displays that behaviour.