The biological approach

• • Assumptions:
  • Everything psychological is first biological.
  • How biological structures and processes within the body impact our behaviour. Much of human behaviour has physiological cause which may be genetically or environmentally altered.
• • Genotype and Phenotype:
  • A person's genotype describes the genetic configuration of an individual, whereas their phenotype describes the combined effects of genetic makeup and surrounding environment on behaviour. It is assumed by this model that mental illnesses can be passed through genetic material. This is studied by looking at the concordance rates of biological relatives.
• • Genetic basis of behaviour:
  • Twin studies are used to see if behavioural characteristics such as intelligence, mental disorders, personality are inherited and are shared by those who are genetically similar.
  • Monozygotic twins (M2) are identical twins who share 100% of their genes
  • Dizygotic twins (D2) are non- identical twins who share 50% of their genes.
  • Psychologists look at the concordance rates between twins- the likelihood that if one twin has a certain trait, the other twin will have the same trait - e.g. if one twin develops schizophrenia, the other twin may develop it too.
• • Continuing genetic basis of behaviour:If concordance rates are higher for MZ twins than DZ twins- it suggests there is a genetic basis.
• • Genotype:
  • This is our genetic makeup- our genetic potential
  • It occurs at conception
  • It dictates characteristics like eye colour and hair colour
  • It is unique to individuals (except from Mz twins)
• • Phenotype:
  • describes the combined effects of genetic makeup and surrounding environment on behaviour
• • Genotype and Phenotype example:
  • twins- have the same genetic potential (genotype) to be 5ft 8
  • But due to the environment (phenotype) like childhood stress, one will be 5ft
• • Evolution and Behaviour
  • proposed by Charles Darwin in the 19th Century
  • The main principle of the theory is natural selection
  • The idea that any genetically determined behaviour that enhances an individual's chances of survival will continue to future generations
  • Those with the most adaptive genetic behaviours reproduce and their offspring too have the adaptive genetic behaviours, enabling their survival.
  • It happens naturally in nature, no one decides which characteristics are advantageous, but the possessor of such characteristics is the most likely to survive
• • The biological is deterministic. For example, it takes the approach that all human behaviour is predictable and inevitable, so someone with a malfunction of the amygdala will always respond aggressively. This is a weakness because this approach ignores the human element of free will and denies the idea that people are self-determining, so someone with a faulty amygdala might engage with strategies to reduce their aggression levels, making their behaviour less predictable.
• • The biological is deterministic. For example, it takes the approach that all human behaviour is predictable and inevitable, so someone with a malfunction of the amygdala will always respond aggressively. This is a weakness because this approach ignores the human element of free will and denies the idea that people are self-determining, so someone with a faulty amygdala might engage with strategies to reduce their aggression levels, making their behaviour less predictable.
• • The biological approach is reductionist. For example, the approach adopts the simplest perspective to explain all human behaviour- that everything has a biological origin. This is a weakness because taking a simple perspective can result in losing the context of behaviour, the biological approach believes that depression is due to serotonin levels, which might result in a clinician overlooking aspects of an individual's life which might contribute to their emotional wellbeing.
• • continuing evaluation: reductionist However, this could also be a strength because adopting a parsimonious (most basic/simple) perspective allows for the development of treatments to be created which can have a positive impact on the lives of patients (e.g. anti-psychotics for schizophrenia)
• There is evidence to support the biological approach. For example, Gottesman (1991) found the following concordance rates for schizophrenia: MZ twins= 48%, DZ twins= 17%, sibling= 9%. This is a strength because the MZ twins have a higher concordance rate than the DZ twins, indicating that schizophrenia is, in part, genetic. If there is no genetic element, then the concordance rates wouldn't be higher for MZ twins. Concordance rate is not 100% for those who have identical DNA, therefore schizophrenia is not entirely geneti
• weakness: cannot seperate nature and nurture: Identical twins, non-identical twins and members of the same family all have genetic similarities. Therefore, the biological approach argues, any similarities in the way that they look or behave must be genetic. However, there is an important confounding variable. They are also exposed to similar environmental conditions.This means that findings could just as easily be interpreted as supporting nurture rather than nature.
• Continuing weakness: This approach also has difficulty accounting for the fact that, in research studies, DZ twins often show higher concordance rates than pairs of ordinary siblings. This is likely to be explained by the influence of nurture as DZs and ordinary siblings both have about 50% (on average) genes in common.