The biological approach

• 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
• Neurochemistry


  The action of chemicals in the brain, much of our thought and behaviour relies on chemical transmission in the brain using neurotransmitters
• Neurotransmitters

  Imbalance has been implicated as a possible cause of mental disorder, e.g. low serotonin in OCD, overproduction of dopamine in schizophrenia
• Genetic basis of behaviour

  Psychological characteristics, such as intelligence, are inherited in the same way as height or eye colour
• Twin studies

  Analyse concordance rates - the extent to which twins share the same characteristic, to investigate whether certain psychological characteristics have a genetic basis
• Genotype


  A person's actual genetic make-up
• Phenotype


  The way that genes are expressed through physical, behavioural and psychological characteristics
• Despite having the same genes, the way identical twins' genes are expressed (the phenotype) is different
• Evolution and behaviour

  The evolution of animals and plants is a fact, and the theory of natural selection proposes that genetically determined behaviour that enhances an individual's survival and reproduction will continue in future generations
• Genetically determined behaviour that enhances an individual's survival and reproduction


  Will continue in future generations
• In nature, selection takes place naturally - no one decides, the selection occurs simply because some traits give the possessor certain advantages
• If the individual survives but does not reproduce, the traits do not remain in the gene pool for successive generations
• Strengths of the biological approach

  • Real-world application in the use of psychoactive drugs to treat mental disorders
  • Use of scientific methods of investigation such as scanning techniques
• Limitations of the biological approach

  • Biological determinism - sees human behaviour as governed by internal, genetic causes over which we have no control
  • Ignores the mediating effects of the environment
• The way in which an individual's genotype is expressed (phenotype) is heavily influenced by the environment
• Not even identical twins who share the same genes look the same and think the same
• A purely genetic argument becomes problematic when considering things such as crime