Biological (medical) approach
The biological approach is different to all other explanations of mind and behaviour. It takes as a basic assumption that all things psychological have a physical cause, be it genes, brain chemistry, brain structure or infection (in the case of abnormal behaviour). However, like the psychodynamic and behaviourist approaches, it does assume a hard determinism of behaviour, but is diametrically opposed to the behaviourists, in that it takes the strictly ‘nature’ stance in the nature-nurture debate.
When it comes to treating psychological illness it proposes the medical model, physical interventions such as drugs or surgery. Psychiatrists follow the physiological model (they start with a training in medicine) psychologists of all flavours on the other hand opt for talking cures.
Unlike the other approaches there aren’t really any specific founding fathers or famous names to rival Freud, Jung, Pavlov, Watson, Skinner, Rogers and Maslow, most medical research and theory now seems to be done as part of larger research teams. However, a few names do spring to mind, for example Sperry, who in 1981, won a Nobel prize for his work on split brain patients.
Genes
A range of physical human characteristics such as hair and eye colour are determined by our genetics. Can psychological traits such as intelligence and personality also be controlled by what we inherit?
Twin studies
Inheritance of characteristics is often tested by comparing the similarity of twins.
Monozygotic twins (MZ) shares 100% of their genetic make-up. If a characteristic such as depression is entirely genetic we would expect that if one twin develops depression the other will too. We would say that there is a 100% concordance rate.
In practice, no psychological disorder has a 100% concordance rate. The highest appears to be bipolar disorder with a concordance rate between MZ twins of around 70%. It seems therefore that genetics is never the whole story. Other factors are needed to trigger the characteristic. We say there is a genetic predisposition.
However, some of that similarity could well be caused by a shared environment. Two identical twins being brought up together in the same house, same school, same friendship groups; it is quite likely that some of their shared behaviour will be learned or acquired from interactions with others and with each other.
Psychologists therefore compare MZ twins with dizygotic (DZ) twins. DZ twins are no more similar than ordinary siblings in that they share 50% of their genetic inheritance with each other. Since these are also brought up together, share the same home environment etc., they make an ideal group for comparison.
The assumption: if MZ twins (100% shared genes) have a higher concordance rate for a characteristic than DZ twins (50% shared genes) then that greater similarity or concordance must be due to their genetics. For example, anorexia nervosa; MZ twins show a concordance rate of 56% compared to only 7% for DZ twins. Holland et al (1984) assume this to be powerful evidence for a genetic predisposition.
Genotype and Phenotype
A physical example: a person with the genotype for coronary heart disease (CHD) might, through careful diet and healthy lifestyle, live to be a ripe old age free of heart trouble. MZ twins, might through different lifestyles and choices grow up to appear quite different. The same applies to psychological disorders and characteristics.
Genes, natural selection and behaviour
You’ll all be familiar with Charles’ Darwin’s theory of natural selection. Physical characteristics that make it more likely that an individual of any species will survive to maturity, reproduce and pass on their genes to the next generation will remain in the gene pool. That characteristic, for example allowing camouflage, greater speed or strength is said to be adaptive
However, behaviours and psychological characteristics can also be adaptive. Examples might include greater intelligence, lower levels of anxiety or greater memory for the location of hidden food caches as in squirrels or nutcrackers.
We would expect characteristics like these to remain in the gene pool. If this is the case, why do psychological disorders such as schizophrenia, depression and anorexia nervosa have a genetic component? Why are they being selected for, rather than against?
The biological approach is different to all other explanations of mind and behaviour. It takes as a basic assumption that all things psychological have a physical cause, be it genes, brain chemistry, brain structure or infection (in the case of abnormal behaviour). However, like the psychodynamic and behaviourist approaches, it does assume a hard determinism of behaviour, but is diametrically opposed to the behaviourists, in that it takes the strictly ‘nature’ stance in the nature-nurture debate.
When it comes to treating psychological illness it proposes the medical model, physical interventions such as drugs or surgery. Psychiatrists follow the physiological model (they start with a training in medicine) psychologists of all flavours on the other hand opt for talking cures.
Unlike the other approaches there aren’t really any specific founding fathers or famous names to rival Freud, Jung, Pavlov, Watson, Skinner, Rogers and Maslow, most medical research and theory now seems to be done as part of larger research teams. However, a few names do spring to mind, for example Sperry, who in 1981, won a Nobel prize for his work on split brain patients.
Genes
A range of physical human characteristics such as hair and eye colour are determined by our genetics. Can psychological traits such as intelligence and personality also be controlled by what we inherit?
Twin studies
Inheritance of characteristics is often tested by comparing the similarity of twins.
Monozygotic twins (MZ) shares 100% of their genetic make-up. If a characteristic such as depression is entirely genetic we would expect that if one twin develops depression the other will too. We would say that there is a 100% concordance rate.
In practice, no psychological disorder has a 100% concordance rate. The highest appears to be bipolar disorder with a concordance rate between MZ twins of around 70%. It seems therefore that genetics is never the whole story. Other factors are needed to trigger the characteristic. We say there is a genetic predisposition.
However, some of that similarity could well be caused by a shared environment. Two identical twins being brought up together in the same house, same school, same friendship groups; it is quite likely that some of their shared behaviour will be learned or acquired from interactions with others and with each other.
Psychologists therefore compare MZ twins with dizygotic (DZ) twins. DZ twins are no more similar than ordinary siblings in that they share 50% of their genetic inheritance with each other. Since these are also brought up together, share the same home environment etc., they make an ideal group for comparison.
The assumption: if MZ twins (100% shared genes) have a higher concordance rate for a characteristic than DZ twins (50% shared genes) then that greater similarity or concordance must be due to their genetics. For example, anorexia nervosa; MZ twins show a concordance rate of 56% compared to only 7% for DZ twins. Holland et al (1984) assume this to be powerful evidence for a genetic predisposition.
Genotype and Phenotype
- Genotype: genetic make-up
- Phenotype: how the genes are expressed (combined with environmental factors)
A physical example: a person with the genotype for coronary heart disease (CHD) might, through careful diet and healthy lifestyle, live to be a ripe old age free of heart trouble. MZ twins, might through different lifestyles and choices grow up to appear quite different. The same applies to psychological disorders and characteristics.
Genes, natural selection and behaviour
You’ll all be familiar with Charles’ Darwin’s theory of natural selection. Physical characteristics that make it more likely that an individual of any species will survive to maturity, reproduce and pass on their genes to the next generation will remain in the gene pool. That characteristic, for example allowing camouflage, greater speed or strength is said to be adaptive
However, behaviours and psychological characteristics can also be adaptive. Examples might include greater intelligence, lower levels of anxiety or greater memory for the location of hidden food caches as in squirrels or nutcrackers.
We would expect characteristics like these to remain in the gene pool. If this is the case, why do psychological disorders such as schizophrenia, depression and anorexia nervosa have a genetic component? Why are they being selected for, rather than against?
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Buss (1989) found that across all human cultures males prefer younger women (allowing for a longer period of fertility) whereas women prefer older men (usually with more resources). In evolutionary terms, men make little investment but can continue producing offspring much later into life. Women on the other hand make a huge physical investment but have a more limited reproductive period. As a result they are more choosy than men and prefer a man who can pay his way! Men also prefer a larger hip to waist ratio… a sign of fertility.
This pattern repeats itself across the animal kingdom. Males often have to go to great lengths to attract a partner. The tail of a peacock is a perfect example. In evolutionary terms and from a point of view of survival, this elaborate appendage is a major hindrance, especially for a largely flightless bird. However, evolutionary pressure from females who see a large tail as a sign of genetic fitness means that only males with the largest, most colourful display get a chance of mating. Only their genes make it to the next generation! Evaluation Sometimes, however, the genetic may not be quite so obvious. For example genes may not be having a direct causal effect, but there may be some intermediary or go-between characteristic that is genetically determined. Addictions seem to have a genetic predisposition, but so does having a risk-taking personality. It’s quite likely that inheriting the latter leads to experimentation with drugs rather than having a gene that makes it more likely that you will become an addict per se. |
Brain chemistry
Clearly chemicals can drastically affect our behaviour and personality. We only have to look at the effects of recreational drugs such as alcohol and cocaine to appreciate that. Many of these drugs are chemically very similar to chemicals in the brain, for example morphine is similar to endorphins and LSD is similar to dopamine. It therefore seems reasonable to assume that varying levels of these brain chemicals could be influential in altering the way we think and behave. Drug therapies turn this assumption to our advantage. We know for example that Prozac alters our levels of serotonin and in some people at least, seems to alleviate some of their depressed symptoms.
The Board don’t really expect you to know a full list of brain chemicals and their various effects on our behaviour; however, a few obvious ones are worth considering:
Adrenaline: increases our levels of arousal, prepares us for a fast response, particularly in the case of emergency. Men appear to be more responsive to the effects of adrenaline and this could be due to our early role in hunting and fighting.
Serotonin: has a variety of roles, but generally appears to be the ‘feel-good’ neurotransmitter that increases our mood and also plays a role in getting us to sleep, in appetite and in pain perception.
Dopamine: known to be involved in addiction. It is released when we do anything that produces pleasure. It is also involved in memory, motor movement and seems to play a role in some forms of schizophrenia.
Brain structure
Psychologists and neuroscientists associate certain brain areas with certain functions, but in general, once again, the situation isn’t that simple.
There are two seemingly opposing general theories on brain function.
1. Localisation of function
This states that various functions such as memory, language, perception, focused attention etc. are situated in specific brain areas. So we have come to associate the pre-frontal cortex with attention and concentration, Broca’s area with speech production and the temporal lobes and hippocampus with memory. On top of this we have cerebral asymmetry, the concept that right and left hemispheres of the brain are responsible for different skills. The right side of the brain is arty and sporty, better at spatial awareness, music and facial recognition, whereas the left is the logical and mathematical side and controls our language.
2. Mass action
Karl Lashely, following his study of rat memory in the early twentieth century, concluded that memories are stored throughout the brain and if one area is damaged, another area can take over its function (equipotentiality principle). This in part led to the bizarre theory, still popularly believed today, that we only use or need 10% of our brains!
In fact there are elements of truth in both theories. Generally, the first is most widely accepted and we now know that certain areas do have certain functions, but also that in any given activity, disparate parts of the brain may all work together. Some have likened it to an orchestra with lots of different sections all contributing to the overall ‘sound.’
Evaluation of the medical model
The medical model is highly scientific. Its use of laboratories and tight control of variables allows for cause and effect relationships to be established and for others to check procedures and allow replication. Research is therefore high in internal validity and very reliable. Its use of observable measures such as scans and other physiological techniques means that it is empirical and highly objective.
It can be claimed with some certainty that there are known biological influences on many behaviours including abnormal conditions, for example, genetic predispositions to certain conditions such as bipolar disorder and schizophrenia. Similarly brain structures are known to be associated with certain functions, such as Brocas and Wernickes with speech production and understanding. In recent years the biological approach has increased our understanding of workplace conditions such as stress and through research into circadian rhythms has allowed a better understanding of shift work.
The medical model has produced many treatments for various psychological conditions, which further strengthen their claim of a biological cause of psychological conditions. Examples include benzodiazepines and beta blockers as treatments for stress and anxiety, SSRIs such as Prozac as a treatment for depression and recently deep brain stimulation (DBI), initially for Parkinson’s but now being as a possible treatment for a range of other disorders too.
However:
The biological model can be seen as reductionist in that it sees humans as little more than machines built from proteins and controlled by electrical impulses and chemicals. As a result there is no consideration of other factors such as thoughts, learning, experience, culture and society, all of which must surely have an impact on whatever it is to be human! At best, the genetic model can only explain predispositions to disorders, never the whole picture.
In a similar vein (no attempt at ‘punnery’ intended), the approach is very deterministic. All that you are is determined for you by your genes, brain chemistry and structure. There is no attempt to explain the sort of person you are in terms of your environment, upbringing, hopes, expectations, feelings etc. As a result its treatments are ‘one size fits all.’ Suffering from depression? Then take one of these twice a day!
As we saw in psychopathology, it isn’t clear to what extent conditions such as depression are caused by a chemical imbalance or create a chemical imbalance. The medical model assumes a causal link and all their treatments take this as a starting point. Remember ‘treatment aetiology fallacy!’ In most cases cause and effect relationships are far from proven.
Evolutionary explanations or cultural influence?
The biological model assumes an evolutionary explanation for any behaviour that is seen as adaptive. However, this may not be the case. More so than in any other species, human behaviour is influenced by social and cultural norms. Incest is clearly disadvantageous from a genetic point of view because of the higher risk of mutation.
Westermarck (1891) suggested a biological effect in which we tend not to form romantic relationships with people with whom we played with in the first six years of life. However, all cultures regard incest as taboo, it is illegal around the world and expressly forbidden by all religions. There are few topics likely to arouse stronger feelings of disgust. However, the reasons for this could be biological, they could be cultural, they are probably both!