The Biological Approach- The Role of Genetics
There are three basic assumptions of the biological approach:
Human behaviour can be explained by looking at biological stuff such as hormones, genetics, evolution and the nervous system
In theory, if we can explain all behaviour using biological causes, unwanted behaviour could be modified or removed using biological treatments such as medication for mental illness
Experimental research conducted using animals can inform us about human behaviour and biological influences because we share a lot of biological similarities
Genetics is used to explain behaviour:
At conception, the egg and sperm join up to give a total of 46 Chromosomes
Each chromosome is made up of a coil of DNA, which in turn is made up of loads and loads of genes
The genes contain the information that makes us unique in appearance (e.g. hair, skin and eye colour)
However, genes are also relevant in psychology, as they are important in the development of the brain, and therefore have a role in our behaviour
The genotype of a person is the genes they have. The phenotype of a person is the characteristic their genes produce- for example; Hair colour, eye colour, etc
Genetics can explain psychological traits:
Faulty genes are known to cause some diseases that have psychological effects, e.g Huntington’s disease which leads to a deterioration of mental abilities
Biological psychologists reckon that genetics can explain ‘psychological traits’. These are things like gender behaviour (things that men and women do differently), intelligence, personality and sexual orientation
They also study genetics to see which genes make some people more likely to develop things like mental illness or addictions
Twin studies and adoption studies are useful for investigating these areas
At first, it was Trikier to investigate brain structure and function
Before brain-scanning techniques were developed, psychologists relied on case studies of people who had experienced a brain injury or had brain operations. If the person had brain damage in a specific area and also a change in behaviour, the assumption could be made that the two were related
For example, in 1848 Phineas Gage had damage to part of his frontal lobe after an explosion at work resulted in an iron bar going straight through his head. After the accident, he was less organised, more impulsive, and more experienced personality changes including increased aggression. This leads to the belief that this area of the brain is responsible for these behaviours. However, this is a case study of only one person, so isn’t representative of the population, which leads to problems with generalising the results
But psychologists can’t just sit around waiting for people with brain injuries to turn up so they can study them. For one thing, studies like that aren’t conducted in controlled circumstances, so they’re less scientific. And ethically we can’t deliberately inflict this type of brain injury on humans. Non-human animals have been used to study brain structure and behaviour, but the differences between non-human animal brains and human brains mean that the results may not be useful when we apply them to human behaviour (and there are still ethics to be considered when animals are used in research). So ideally psychologists could do with another way of studying brain structure and behaviour.
Brain scans can help examine patterns of brain activity and anatomy:
There are five basic techniques used:
PET scans (positron emission tomography) show which parts of the brain are active during different tasks. By studying PET scans, we can link certain areas of the brain with particular functions. They also allow us to see where the brain is most active when we are thinking about certain things. They show average activity over 60 seconds, not moment-by-moment
CAT scans detect damaged parts of the brain, tumours and blood clots. Brain structure is shown, not function
MRI scans detect small tumours and provide detailed information about the structure
Functional MRI scans provide structural and functional information
SQUID magnetometry produces accurate images of brain activity by measuring the magnetic fields generated when neurons are activated. However, outside sources of magnetism can affect measurements
Brain structure has been investigated in several areas of psychology:
Aggression- Bard and Mountcastle (1948) found that lesioning (i.e. damaging) areas of the brains of cats led to changes in levels of aggression. Their research suggests that the hypothalamus and amygdala are involved in aggression
Memory- In a case study, Milner et al (1957) found that HM was unable to use his long-term memory effectively, suggesting that the hippocampus has an important role here
Psychopathology- Szeszko et al (1995) found differences in the prefrontal cortex when comparing people with and without schizophrenia, suggesting a relationship between them
Neurochemistry might also influence behaviour:
Neurochemistry is all about the nervous system and neurotransmitters. The biological approach looks at the role they might play in explaining behaviour
Too much or too little of a particular neurotransmitter may produce psychological disorders, e.g. an increased level of dopamine is linked to schizophrenia. Drugs like cocaine, which increase dopamine levels, can lead to schizophrenia-like symptoms
Some biological psychologists investigate the impact neurotransmitters have on behaviour.
The biological approach has strengths and weaknesses:
Strengths:
The approach can provide evidence to support or disprove a theory- it’s a very scientific approach
If a biological cause can be found for mental health problems or unwanted behaviour such as aggression, then biological treatments can be developed to help individuals
Weaknesses:
The approach doesn’t take into account the influence of people’s environment, their family, childhood experiences or their social situation. Other approaches see these as being important factors in explaining behaviour
Using a biological explanation for negative behaviour can lead to individuals or groups avoiding taking personal or social responsibility for their behaviour
There are three basic assumptions of the biological approach:
Human behaviour can be explained by looking at biological stuff such as hormones, genetics, evolution and the nervous system
In theory, if we can explain all behaviour using biological causes, unwanted behaviour could be modified or removed using biological treatments such as medication for mental illness
Experimental research conducted using animals can inform us about human behaviour and biological influences because we share a lot of biological similarities
Genetics is used to explain behaviour:
At conception, the egg and sperm join up to give a total of 46 Chromosomes
Each chromosome is made up of a coil of DNA, which in turn is made up of loads and loads of genes
The genes contain the information that makes us unique in appearance (e.g. hair, skin and eye colour)
However, genes are also relevant in psychology, as they are important in the development of the brain, and therefore have a role in our behaviour
The genotype of a person is the genes they have. The phenotype of a person is the characteristic their genes produce- for example; Hair colour, eye colour, etc
Genetics can explain psychological traits:
Faulty genes are known to cause some diseases that have psychological effects, e.g Huntington’s disease which leads to a deterioration of mental abilities
Biological psychologists reckon that genetics can explain ‘psychological traits’. These are things like gender behaviour (things that men and women do differently), intelligence, personality and sexual orientation
They also study genetics to see which genes make some people more likely to develop things like mental illness or addictions
Twin studies and adoption studies are useful for investigating these areas
At first, it was Trikier to investigate brain structure and function
Before brain-scanning techniques were developed, psychologists relied on case studies of people who had experienced a brain injury or had brain operations. If the person had brain damage in a specific area and also a change in behaviour, the assumption could be made that the two were related
For example, in 1848 Phineas Gage had damage to part of his frontal lobe after an explosion at work resulted in an iron bar going straight through his head. After the accident, he was less organised, more impulsive, and more experienced personality changes including increased aggression. This leads to the belief that this area of the brain is responsible for these behaviours. However, this is a case study of only one person, so isn’t representative of the population, which leads to problems with generalising the results
But psychologists can’t just sit around waiting for people with brain injuries to turn up so they can study them. For one thing, studies like that aren’t conducted in controlled circumstances, so they’re less scientific. And ethically we can’t deliberately inflict this type of brain injury on humans. Non-human animals have been used to study brain structure and behaviour, but the differences between non-human animal brains and human brains mean that the results may not be useful when we apply them to human behaviour (and there are still ethics to be considered when animals are used in research). So ideally psychologists could do with another way of studying brain structure and behaviour.
Brain scans can help examine patterns of brain activity and anatomy:
There are five basic techniques used:
PET scans (positron emission tomography) show which parts of the brain are active during different tasks. By studying PET scans, we can link certain areas of the brain with particular functions. They also allow us to see where the brain is most active when we are thinking about certain things. They show average activity over 60 seconds, not moment-by-moment
CAT scans detect damaged parts of the brain, tumours and blood clots. Brain structure is shown, not function
MRI scans detect small tumours and provide detailed information about the structure
Functional MRI scans provide structural and functional information
SQUID magnetometry produces accurate images of brain activity by measuring the magnetic fields generated when neurons are activated. However, outside sources of magnetism can affect measurements
Brain structure has been investigated in several areas of psychology:
Aggression- Bard and Mountcastle (1948) found that lesioning (i.e. damaging) areas of the brains of cats led to changes in levels of aggression. Their research suggests that the hypothalamus and amygdala are involved in aggression
Memory- In a case study, Milner et al (1957) found that HM was unable to use his long-term memory effectively, suggesting that the hippocampus has an important role here
Psychopathology- Szeszko et al (1995) found differences in the prefrontal cortex when comparing people with and without schizophrenia, suggesting a relationship between them
Neurochemistry might also influence behaviour:
Neurochemistry is all about the nervous system and neurotransmitters. The biological approach looks at the role they might play in explaining behaviour
Too much or too little of a particular neurotransmitter may produce psychological disorders, e.g. an increased level of dopamine is linked to schizophrenia. Drugs like cocaine, which increase dopamine levels, can lead to schizophrenia-like symptoms
Some biological psychologists investigate the impact neurotransmitters have on behaviour.
The biological approach has strengths and weaknesses:
Strengths:
The approach can provide evidence to support or disprove a theory- it’s a very scientific approach
If a biological cause can be found for mental health problems or unwanted behaviour such as aggression, then biological treatments can be developed to help individuals
Weaknesses:
The approach doesn’t take into account the influence of people’s environment, their family, childhood experiences or their social situation. Other approaches see these as being important factors in explaining behaviour
Using a biological explanation for negative behaviour can lead to individuals or groups avoiding taking personal or social responsibility for their behaviour
