The Biological Approach

– Predates psychology but established in the 1980s due to advances in technology

– Emphasises the importance of physical processes in the body such as genetic inheritance

– Suggests that everything psychological is at first biological so to fully understand behaviour we must look at biological structures and processes within the body, such as genes and neurochemistry

– On the nature side of the debate

– Biologically determinist

– Biologically reductionist



– View humans as biological organisms and so provides biological explanations for all aspects of psychological functioning

– All behaviour is innate and biological and is due to internal influences

– Behaviour has a genetic basis as characteristics can be inherited from generation to generation

– Chemicals, neurochemistry and hormones also influence behaviour

– Evolution can explain the original adaptive behaviours such as aggression in males



Hereditary – The passing of characteristics from one generation to the next through genes

Genes – A part of the chromosome of an organism and carries the information of DNA

– Codes the physical and psychological features of an organism

– Inherited from biological parents

– The inheritance of genes is how offspring take after their parents

– The genes carry the instructions for particular characteristics but how this characteristic develops depends on the interaction of the gene with other genes and the environment

– The extent to which a psychological characteristic is determined by genes or environment is called the nature-nurture debate

Twin Studies

– Used to determine the likelihood that certain traits have a genetic basis by comparing the concordance rates of pairs of twins: to which extent do they share the same characteristic

– If identical (monozygotic) twins are found to have higher concordance rates than non-identical (dizygotic) twins this would suggest a genetic basis

– This is because monozygotic (MZ) share 100% of each other’s genes whereas dizygotic (DZ) twins share about 50% (the same as normal siblings)

Genotype – The genetic makeup of an individual that is written in the DNA of the individual’s cells

      – Collection of inherited genetic material that is passed from generation to generation

Phenotype – The way that genes are expressed through physical, behavioural and psychological characteristics

       – The characteristics of an individual determined by both genes and environment

– Expression of a phenotype is influenced by environmental factors, e.g identical adult twins can look different due to factors such as exercise, hair dye, etc.

– For example, PKU is a rare genetic disorder that can be detected in babies

– If left unchecked PKU causes severe learning difficulties in those who carry the genotype

– If detected early enough the child can be placed on a restricted diet and develop normally

– This illustrates that much of human behaviour depends on an interaction between inherited factors (nature) and environment (nurture)

– The evolution of animals and plants is a fact

– In the 19th century, Darwin proposed a theory to explain it.

– Genetically determined behaviour that enhances an individual’s survival and reproduction will be passed onto future generations

– The genes will be naturally selected.

– In nature, this happens as there was a large genetic variation in the population

– The traits that made the possessors more likely to survive were passed on as the possessors were able to survive (because of these traits) and were able to reproduce and pass on their traits



The importance of the scientific method

– The biological approach uses the scientific method and uses the experimental method of investigation.

– Experimental studies take place in highly controlled environments so that other researchers are able to replicate research studies under the same experimental conditions

– This is because they use standardised instructions

– Thus, adding to the reliability of the original findings if they can be reproduced.

– This also means that they are able to establish cause and effect of their findings meaning they know that the DV directly affects the IV due to high control and less extraneous variables

– Therefore, the use of the scientific method adds reliability to their findings but also scientific credibility to psychology


Treating psychological disorders

– The biological approach has increased our understanding of biochemical processes in the brain

– This has led to the development of psychoactive drugs that treat serious mental illnesses, such as depression

– Biological treatments act directly on the biological mechanisms that cause, or are involved in, mental illness.

– This can be, for example, by altering the function or availability of a neurotransmitter, changing the way certain cells in the nervous system function, or removing dysfunctional parts of the nervous system.

– Antipsychotic drugs, which are often used to treat schizophrenia, work by reducing the amounts of dopamine at synapses in certain areas of the brain.

– Although these drugs are not effective for all patients, they have revolutionised treatment and the lives of many

– This is a strength of the biological approach because it means that suffers are able to manage their condition and live a normal life, rather than stay in the hospital

– Therefore, the biological approach has used drug treatments to better many people’s lives


Biologically Deterministic

– Sees human behaviour as governed by internal, biological causes over which we have no control.

– Implying it’s a strong supporter of the nature debate.

– This could have an effect on our legal system as if a criminal gene was ever found this would mean that offenders would no longer be liable for their actions as they were determined by their genes

– Therefore, they would not be able to be punished and would not take responsibility for their actions

Biologically Reductionist

– This is the belief that complex human behaviour can be explained by breaking it down into its smallest components, such as the action of genes, neurochemicals and hormones.  

– For example, many explanations of mental health are reductionist because genes or neurochemical imbalances are believed to be the main causes of these disorders.

– However, this approach doesn’t take culture, social life or families into account and how these may have influenced their mental disorders

– These include cognitive, emotional and cultural factors all of which have a significant influence on behaviour

– Therefore, we cannot fully understand behaviour without also taking account the other factors that influence it, but the biological approach only considers the biological factors

Twin Studies

– Monozygotic and dizygotic twins and members of the same family all have genetic similarities.
– The biological approach argues that similarities must be genetic.

– However, the twins are also exposed to the same conditions.
– Identical twins are also treated the same a lot of the time, meaning not only is their biology identical but so is their environment

– Additionally, the concordance rates for MZ are never 100% so some behaviour must be explained by nature and not nurture

– Therefore, biology only can explain the similarities between the twins but not the differences, which must be explained by nurture.