Biological Approach Flashcards
Basic assumptions of the biological approach
*All behaviour can be explained in terms of physical factors and our biological make-up including:
o Genes - psychological characteristics can be inherited from parents through their genes in the same way as physical features such as eye colour are inherited.
o Evolution - psychological features are the result of evolution. These features exist because they helped us to survive and reproduce over the many years of our evolution.
o The brain (and other aspects of the nervous system)
o Neurochemicals
o Hormones
*Research within the biological approach tends to be highly scientific. Common research methods used include laboratory experiments and brain scanning techniques
*According to Darwin’s theory of evolution there is behavioural continuity between species. Biological psychologists therefore see the study of animals as useful in understanding human behaviour.
2 influences of genes on behaviour
genetic basis of behaviour, genotype and phenotype
Genetic basis of behaviour
The genes we have we inherit from our parents and they in turn have inherited their genes from their parents. Close members of a family have some genes in common and that is why people are often similar to others in their family. The biological approach believes that genes create psychological characteristics such as temperament, aggression, mental illness etc. as well as physical characteristics.
Many geneticists are attempting to find a candidate gene for a disorder- this means focusing on the particular selection of genes that have been in some way related to the disease
Some characteristics are more heavily influenced by genes than others. The extent to which any characteristic is influenced by genes is called heritability and this can be investigated using twin studies.
Twin studies compare how often identical twins (monozygotic) have the same psychological characteristic (such as a mental illness, musical ability, love of sport etc.) compared to how often non-identical twins (dizygotic) have the same psychological characteristic. The measurement of how often they have the same characteristic is called concordance and is expressed as a percentage.
Genotype and phenotype
The specific genetic make-up of any individual is called their genotype. Each person is thought to have about 100,000 genes on 23 pairs of chromosomes that have come from their two biological parents. Each person has a unique genotype (unless they are an identical twin) that depends upon the way their two parents’ genes combined at conception.
Phenotype is how the genes are expressed in physical, behavioural and psychological characteristics. The phenotype is influenced by the genes that someone has in combination with the experiences that they have had and the environmental they have lived
For example - an individual might have inherited a gene that is linked to becoming a psychopath. Whether this gene actually influences them to become a psychopath depends upon the life experiences that they have. Positive experiences in life would mean the person did not demonstrate the behaviours and attitudes of a psychopath whereas negative life experiences would mean that they might become a psychopath.
The phenotype (being a psychopath) occurs as a result of both genes and experiences. Many psychologists believe that human behaviour is usually the product of both nature and nurture and that your genotype does not automatically determine the psychological characteristics you will have.
Evaluation of the influence of genes on behaviour, supporting evidence
*There is supporting evidence for the role of genes in behaviours. For example, research into OCD has found a concordance rate of 68% for identical twins compared to 31% in non-identical twins. This means that where one identical twin has OCD, 68% of the time the other twin will also have the same condition. In non-identical twins both of them will have the condition 31% of the time. As the only difference between the two types of twin is how genetically similar they are, if two identical twins both have the same characteristic more often than two non-identical twins then logically this can only be because they have the same genes. So the example above suggests that OCD is influenced by genes.
*Furthermore, there is more supporting evidence. Research has identified two potential candidate genes for OCD. The COMT gene, which controls the production on an enzyme that regulates dopamine, and the SERT gene: A mutation of this gene (which is implicated in the breakdown of serotonin) is found in families who live with OCD
Evaluation of the influence of genes on behaviour, criticism
*However, a criticism is there are significant problems with twin studies which limits the conclusions we can draw from these. Notice that the concordance rate for identical twins for OCD is not 100%. This suggests that even though genes do seem to have a role to play in developing this condition simply having a particular gene does not mean that the condition will always develop. It seems that some characteristics appear as a result of both genetic factors and experiences in life.
Evolution and behaviour
The biologists assume that modern human behaviour is the result of natural selection and that evolution can explain psychological attributes in the same way as Charles Darwin explained the evolution of physical features.
Evolution is based on the effects of genes on behaviour. A gene mutation creates a new version of a gene that might give some useful behaviour that increases the chances of survival. A behaviour that increases the chances of survival is called adaptive behaviour. The person with that gene survives and is able to reproduce and their offspring would inherit that gene and so on. This gene would become widespread over time and form part of the genotype that persists in the human population today. The gene has been “naturally” selected.
Evaluation of the role of evolution, research support
*There is some research to support the role of evolution on behaviours. For example, an early human might have a gene mutation that meant they really liked the taste of sweet foods and hated bitter foods. Sweet foods are rarely poisonous but bitter foods are so this person would not eat poisonous food. They would survive better than someone who did not like sweet foods so much and ate bitter foods. Modern humans everywhere like the taste of sweet food because we have the sweet taste gene within our genotype according to this explanation.
Evaluation of the role of evolution, criticism
*However, a criticism with the evolutionary approach to explaining behaviour is that it lacks testability. This is because it is impossible to actually test the selective pressures on our species in our evolutionary history. As a result, this theory does not meet the criteria for science and may be consider to be pseudoscientific.
The influence of biological structures on behaviour
Specific regions of the brain are linked with specific processes such as hearing, speaking, comprehension, face recognition etc.
The outer layer of the brain is termed the cerebral cortex and has been identified as being responsible for (influencing) higher order functions such as thought and language. Damage to these areas can result in disturbances in thought or language.
The language centre is in the left hemisphere in most people.
One area that is important in dealing with language processing, is Broca’s area This is a small area in the frontal lobe of the left hemisphere and it is responsible for the production of speech. People who have damage to this area have very slow, laborious speech that lacks fluency in a condition called Broca’s aphasia.
Furthermore, abnormal behaviours may occur if the structure of the brain is damaged or in some way unusual. For example, brain scans of schizophrenic patients have shown that those with the disorder have enlarged ventricles, when compared with those not suffering from the disorder.
The influence of neurochemistry on behaviour
This refers to chemicals in the body such as neurotransmitters. A neurotransmitter is a chemical that allows messages to be transmitted across gaps in the nerves.
There is much evidence to suggest that neurotransmitters are linked to mental illness. For example, Mann et al (1996) found that depression is associated with reduced levels of serotonin.
Another idea is that OCD is caused by a disruption of serotonin levels which has a knock-on effect on regulating the levels of other neurotransmitters, such as glutamate, GABA, and dopamine. This idea is based on the reduction in symptoms of OCD seen in individuals who take anti-depressant drugs that increases serotonin activity.
Evaluation of the role of biological structures AND neurochemistry, criticism
*It is very difficult to determine cause and effect between an individual’s biology and mental illness. It is not clear whether chemical / structural abnormalities in people with OCD/ schizophrenia / depression are a cause of the condition or develop as a result of the condition. This is a weakness because the explanation does not fully explain what it set out to.
Evaluation of the biological approach, strength
*The biological approach is a scientific way of investigating behaviour. It relies on carefully controlled experimental techniques to research its assumptions and the use of highly precise and objective scanning techniques mean that direct, empirical evidence can be gained about biological processes. The use of the scientific method means that this approach has greatly contributed to the emergence of psychology as a scientific discipline.
Evaluation of the biological approach, criticism
*There is an on-going debate in psychology about the relative contributions of nature and nurture to our behaviour. The biological approach regards nature as being largely responsible with little regard to the effects of experiences on our behaviour. Many critics feel that this makes the approach unbalanced as they think that human behaviour is almost always the product of a combination of biological factors (nature) and experiences in our environment (nurture).
*The biological approach assumes that humans have very little ability to influence or control their behaviour as internal factors such as genes or brain chemistry are what make us behave as we do. This makes it a determinist approach as it does not accept that humans can make conscious decisions and act according to their free will. This can be a particular problem if someone should claim that they are not responsible for anti-social actions such as aggression because they have a gene that makes them behave so. This could allow an offender to escape a guilty conviction if they could show that they could not help their behaviour.
Evaluation of the biological approach, practical application
*The biological approach has considerable value in that its ideas have very useful practical applications. Research into the effects of neurotransmitters for example has led to the development of drugs that can correct imbalance associated with mental illness. For example, SSRI’s are used to treat OCD and affect levels of serotonin. Other research into biological processes such as the timing of bodily rhythms such as the sleep wake cycle have been useful in changing shift work practices to improve the well-being of people who need to work through the night time.
