The Biological Approach

• The Biological Approach:

  • The biological approach is the influence of genes, biological structures and neurochemistry on behaviour.
  • Genotype and phenotype, genetic basis of behaviour, evolution, and behaviour.
• Assumptions: AO1:

  • Everything psychological is at first biological.
  • The approach investigated how biological structures and processes within the body impact behaviour.
  • Genes affect behaviour and influence individual psychological differences between people.
  • Evolutionary psychology considers genetic influences in common behaviours.
  • Psychologists should study the brain, nervous system, and other biological systems.
  • The mind lives in the brain, meaning that all thoughts, feelings, and behaviours ultimately have a physical basis.
• Genes: AO1:

  • Genes are the genetic information carried by DNA in chromosomes, found within a cell’s nucleus; they are passed on through generations of a species if individuals survive and successfully reproduce.
  • In line with Darwin’s theory of evolution, it might also follow that genes form a basis of behaviour, as both behaviour and genes appear to be heritable.
  • An example might be aggressive behaviour, in light of obvious survival benefits such as warding off predators and competing for resources.
• Genotype:

  The genotype is the particular set of genes that a person possesses, made up of DNA.

  Genes only determine the potential for characteristics (genotype).
• Phenotype:

  • Phenotype describes the combined effects of genetic makeup and surrounding environment on behaviour.
  • The observable characteristics of an individual depend on the interaction of genetic and environmental factors.
• Twin Studies:

  • Identical twins (same genotype) may have the same genes, but one may spend more time in the sun - or exercise more.
  • Example - PKU is a genetic disorder that can lead to severe learning difficulties unless it is caught and the child is following a strict diet.
  • Twin studies are used to determine the likelihood that certain trains have a genetic basis.
  • By comparison of concordance rates.
  • This is the extent to which both twins share the same characteristics.
• Concordance Rates: AO1:

  • The extent to which both twins share the same characteristics.
  • There should be a 100% concordance rate between identical (MZ) Twins.
  • Fraternal (DZ) Twins can be made between twins raised together, and twins raised apart.
• Research into the influence of genes:

  • McGuffin et al (1996) found that if one identical twin (MZ) has depression, there is a 46% chance that the other twin will also have depression.
  • For DZ Twins, there was a 20% chance that the other twin would also have depression.
  • This suggests there is a genetic component to illnesses like schizophrenia and depression.
  • If the identical twins have a higher concordance rate than the non-identical twins, then that shows that there is a genetic element involved.
• Biological Approach AO3: Strength:

  • It makes use of a range of precise and highly scientific methods.
  • For example, these include scanning techniques such as fMRI’s, and ECG’s. Additionally, twin and drug studies are also used widely.
  • These advances in technology mean it is possible to accurately measure biological and neural processes in ways that are not open to bias, increasing the overarching levels of reproducibility and allowing methods of diagnosis to be investigated and furthered.
• Biological Approach AO3: Weakness:

  • Fails to acknowledge the significance of the difference between the nature vs nurture debate.
  • For example, Twin studies highlight how DZ and MZ twins all share similar genetics.
  • McGuffin et al (1996) found that if one identical twin (MZ) has depression, there is a 46% chance that the other twin will also have depression.
  • For DZ Twins, there was a 20% chance that the other twin would also have depression.
  • There is a genetic component to illnesses like schizophrenia and depression.
  • On the other hand, it may lead to a reductionist view of genetics as superior, when in reality both aspects (biological and environmental) have a great impact on the development of certain characteristics.