Biological Approach Flashcards
Assumptions of the biological approach:
- Our biology is determined by evolution and genetics
- To investigate the mind, we must investigate the physical brain
Allele
Different forms of the same gene in different people
Genes
A section of DNA with genetic code for making enzymes and hormones.
They control the development of characteristics and contain code for functioning of CNS structures like the brain and spinal cord.
If problems occur in the genes:
Leads to problems with structure and function of CNS and therefore problems with behaviour.
Genes linked to human behaviour
Researchers have found that genes have led to vulnerability for OCD.
Faulty 5HTT gene leads to issues with the transportation of serotonin which causes lower levels of serotonin in the synapse - resulting in OCD.
5HTT
Mechanism that transports serotonin
Faulty 5HTT
Causes OCD
The brain
Controls our daily behaviour and is responsible for the production of our thoughts, emotions and sensations.
The cerebral cortex
Deals with higher order functions such as thought and language
When the brain suffers damage:
Leads to change in our behaviour as it effects our thinking pattern
Neurotransmitters:
Chemical messengers that travel across synapses to deliver messages between neurons.
How does the brain communicate?
Through chemicals and electrical impulses
Dopamine
Excitatory neurotransmitter
Increases the likelihood of firing (associated with drive)
Serotonin
Inhibitory NT
Decreases likelihood of firing (associated with mood stabilisation)
Low levels of serotonin:
Can lead to depression
High levels of dopamine:
Associated with anxiety
Evolution and Behaviour
- Random mutation
- Leads to adaptive characteristics
- Better suited to survive
- Natural selection
- Genetically pass on the traits which helped you survive
- Carried this on for each successive generation
- Evolve
Natural selection
Any genetically determined behaviour which increases a species survival will be passed down to future generations
A strength of genetic explanations of human behaviour is the supporting evidence from twin studies.
McGuffin conducted a twin study on depression - CR for MZ twins: 46% and for DZ twins was 20%.
Proportion of shared genes and genetic similarity increases when comparing MZ to DZ, the likelihood of both twins showing trait of depression also increases.
Suggests depression is partly genetic since twins who are genetically identical are twice as likely to both have the same disorder than non-identical twins.
Increases in validity.
A strength of the Biological approach is that there is practical application of biochemical explanations:
Our understanding of the impact of neurotransmitters on brain functioning and behaviour has led to the development of drugs which alter the levels of NT in the brain.
Knowing low levels of serotonin lead to depression, led to antidepressants such as SSRIs which increase levels of serotonin in brain which can alleviate symptoms.
Giltin found that antidepressants are effective in reducing symptoms in 65-75% of cases.
Since treatment is valid and based on assumptions of the BA, we can assume the BA is also valid.
SSRI
Selective serotonin reuptake inhibitance
A weakness of biological approach is that the evidence it relies on (twin studies) has questionable validity.
Twin studies assume that MZ twins CR is higher than DZ because they share 100% of their genes whilst DZ twins share 50%.
In doing so, BA fails to account for the fact that MZ twins look identical to each other and are therefore more likely to be treated similarly by their environment than DZ twins.
Therefore, the higher MZ CR may not be due to genes, but instead the environment.
A limitation of BA is that it is reductionist.
It oversimplifies complex behaviour such as internal mental processes down to genes and neurotransmitters and therefore fails to account for the role of environmental factors.
The diathesis stress model proposes that genes make an individual more vulnerable to developing a behaviour, but that an environmental trigger is necessary for the behaviour to occur.
Shows that BA by itself does not account for the interaction of diff factors and therefore can be considered incomplete and reduces the validity.
To better understand behaviour, we should take a holistic approach and consider both biology and environment.
The diathesis stress model
Proposes that genes make an individual more vulnerable to developing a behaviour, but that an environmental trigger is necessary for the behaviour to occur.
