Biological Approach - Genetics and Biological structures Flashcards
Key assumptions of biological approach
- Behaviour has evolved through evolutionary adaptation.
- The genes an individual possesses influence their behaviour.
- The biological examination of animals can provide useful information about
human behaviour. - Biological structures and neurochemistry control and influence our reactions
to the environment.
Evolution
According to Charles Darwin, our behaviour has adapted and changed over time through natural selection. This is where profitable behaviours are selected in mates and therefore reproduced. Over time, advantageous behaviours will continue which will continually increase our ability to survive.
Influence of genetics
Heredity refers to the idea that characteristics are ‘passed on’ from one generation to the next through our genetics. These characteristics can be physical (e.g. height and hair colour) or psychological (e.g. intelligence and predisposition to mental illness). To examine the extent to which genes influence behaviour, work is often carried out on pairs of twins. These studies often involve comparing the likelihood of a behaviour/disorder occurring in identical twins (who are 100% genetically similar) to the likelihood of the behaviour/disorder occurring among non-identical twins (who are 50% genetically similar). If the MZ twins show a higher concordance rate (shared behaviour) then there is argued to be a genetic component.
It is very rare, however, that the concordance rate for MZ twins is 100%. This suggests that, although there may be a genetic influence, some behaviours could be a mix of both genetics and environment
Phenotype
Refers to the observable traits/characteristics shown by an individual that are due to the combined effect of genes and environment.
Genotype
Refers to the genes an individual possesses i.e. an individual’s genetic make-up.
Biological structures
The Nervous System is divided into:
- The Central Nervous System: This comprises of the brain and spinal cord which act as the centre from which the individual is controlled e.g. through the cognitive processing of the brain.
- The Peripheral Nervous System: This comprises of the somatic nervous system and autonomic nervous system. The somatic nervous system comprises the muscles attached to the skeleton and is therefore pivotal for movement. The autonomic nervous system oversees bodily organs and is involved in the fight or flight response.
The endocrine system maintains levels of hormones in the blood that are released by glands. The most important gland is the pituitary gland which is located in the brain. This is sometimes called the master gland because it instructs the other glands in the body to secrete hormones when necessary.
Advantages of Genetics
1) An advantage of examining genes and the role they have on behaviour is that gene mapping can help psychologists locate genes on chromosomes which is highly scientific and objective. Therefore investigating genes involves precise methods of investigation which would be supported by science (+)
2) An advantage of studying genetics is that it often involves using twin and adoption studies. This is very useful when examining MZ (monozygotic twins) who are identical as it can help psychologists examine concordance rates in relation to behaviour. The research by Gottesman and Shields would support the idea that certain illnesses such as schizophrenia are transmitted genetically (+)
3) Genetics has the advantage in that it can help psychologists screen people to see if they carry genes for certain illnesses. This would involve gene mapping and it can help psychologists identify individuals who might be at risk from certain illnesses or diseases such as depression or some forms of cancer. This means that people might get psychological help before they become unwell (preventative) (+)
Disadvantages of Genetics
4) A disadvantage when examining the role of genetics is that it is reductionist. It takes a complex human behaviour such as IQ and reduces it down to small components alone such as genes. This idea seems inaccurate, as IQ is not solely dependent on genes; other factors need to be considered such as the environment (-)
5) The role of genes and its effect on behaviour and be criticised, because other models and approaches in Psychology are being ignored. For example the cognitive and behavioural approaches would also need to be considered when examining behaviour. An example is that someone who has depression might carry the gene for depression, but they might also have faulty and negative cognitions which have been ignored. (-)
Advantages of Evolution
1) Evolutionary ideas can be supported by the nature side of the nature and nurture debate. The evolutionary approach states that our biology (genetic makeup) and interactions with the environment have a direct effect on our behaviour, for instance genetic mutations of genes in giraffes have led to them having very long necks so that they can get enough food in the environment and reach the top leaves from the tree. (+)
2) The evolutionary approach is heavily supported by the work from Charles Darwin and survival of the fittest. This can help explain how certain traits become adaptive within a species such as males being very tall, or giraffes having long necks
(+)
3) Evolutionary ideas have their advantages because it means that species will compete with each other in order to seek the best mate to reproduce with. This helps to maximize the chances of healthy offspring being produced who will be healthy and will be able to pass on their genes to the next generation. This helps human/animal species to evolve and adapt (+)
Disadvantages of Evolution
4) A problem of the idea of evolution is that is does not clearly explain some behaviours and how or why they might be adaptive. For instance OCD has been found to be genetic, but it is not clear how OCD can be adaptive and can help aid survival of the fittest. This is not very clear and is not well explained. (-)
5) The idea of evolution can be criticised because it fails to take into account behavioural and cognitive explanations for behaviour. The idea of every species wishing to reproduce and aid survival seems to take away the idea of free will and cognitions, whereby not all members of a species have this drive or will make such decisions. (-)
Advantages of Biological Structures
1) The biological model has its strengths in that the study of the brain relies on the use of scans, such as PET (Positron Emission Tomography) and MRI (Magnetic Resonance Imaging) and post mortem studies which adds to scientific evidence than can help support the biological approach. It can be viewed as one of the most scientific models/approaches (+)
5) An advantage of looking at brain structures is they can be scientifically and objectively investigated in order to test how they might affect behaviour. For instance the brain can be investigated using FMRI and PET scanning which gives psychologists access to investigating and understanding how the brain functions (+)
Disadvantages of Biological Structures
2) The biological model can be criticised because it is more applicable at explaining the causes of some behaviours, but not others. For instance infection or neuroanatomy of the brain can cause schizophrenia, but there are some behaviours that cannot be well explained by these ideas. For instance the development of phobias is usually learnt (-)
3) Cause and effect is a disadvantage when looking at biological structures and their effect on behaviour. For instance can psychologists be sure that a brain malfunction is causing a behaviour to occur, e.g. a smaller hypothalamus causing schizophrenia? (-)
4) A problem of studying the brain is that psychologists still do not know 100% about the brain and its functions. Therefore there could be problems of trying to identify which part of the brain is responsible for certain behaviours and more investigation might be needed. (-)
