The Biological Approach
Assumptions
The biological approach suggests that everything psychological is at first biological, so to fully understand human behaviour, we must look to biological structures and processes within the body, such as genes, neurochemistry and the nervous system. An understanding of brain structure and function can explain our thoughts and behaviour. From a biological perspective, the mind lives in the brain – meaning that all thoughts, feelings and behaviour ultimately have a physical basis. This is in contrast to, say, the cognitive approach that sees mental processes of the mind as being separate from the physical brain.
The Genetic Basis of Behaviour
Behaviour geneticists study whether behavioural characteristics, such as intelligence, personality, mental disorder, etc., are inherited in the same way as physical characteristics such as height and eye colour. Twin studies are used to determine the likelihood that certain traits have a genetic basis by comparing the concordance rates between pairs of twins; that is, the extent to which both twins share the same characteristic. If identical (monozygotic) twins are found to have higher concordance rates than non-identical (dizygotic) twins – for musical ability, schizophrenia, love of romantic films or whatever – this would suggest a genetic basis. This is because MZ twins share 100% of each other’s genes, whilst DZ twins share about 50% (the same as any siblings).
Genotype and Phenotype
A person’s genotype is their actual genetic makeup, whereas phenotype is the way that genes are expressed through physical, behavioural and psychological characteristics. The expression of a genotype is inevitably influenced by environmental factors. For instance, identical adult twins usually look slightly different because one has exercised more or one has dyed their hair and so on. So, despite having the same genes, the way identical twins’ genes are expressed (the phenotype) is different – see also the example of PKU (opposite). This illustrates what many biological psychologists would accept, that much of human behaviour depends upon an interaction between inherited factors (nature) and the environment (nurture).
Evolution and Behaviour
The evolution of animals and plants is a fact. In the 19th century, Charles Darwin proposed a theory to explain this fact – the theory of natural selection. The main principle of this theory is that any genetically determined behaviour that enhances an individual’s survival (and reproduction) will continue in future generations, i.e. be naturally selected. This happens in a similar way to a farmer deciding which animals to use for breeding – the farmer selects the ones who possess desirable characteristics. For example, if one of a farmer’s cows has a high milk yield the farmer chooses this cow for further breeding so his stock of cows become progressively better milk producers. In nature this selection takes place ‘naturally’ – no one ‘decides’, the selection occurs simply because some traits give the possessor certain advantages. The possessor is more likely to survive, reproduce and pass on these traits. If the individual survives but does not reproduce, the traits do not remain in the gene pool.
Assumptions
The biological approach suggests that everything psychological is at first biological, so to fully understand human behaviour, we must look to biological structures and processes within the body, such as genes, neurochemistry and the nervous system. An understanding of brain structure and function can explain our thoughts and behaviour. From a biological perspective, the mind lives in the brain – meaning that all thoughts, feelings and behaviour ultimately have a physical basis. This is in contrast to, say, the cognitive approach that sees mental processes of the mind as being separate from the physical brain.
The Genetic Basis of Behaviour
Behaviour geneticists study whether behavioural characteristics, such as intelligence, personality, mental disorder, etc., are inherited in the same way as physical characteristics such as height and eye colour. Twin studies are used to determine the likelihood that certain traits have a genetic basis by comparing the concordance rates between pairs of twins; that is, the extent to which both twins share the same characteristic. If identical (monozygotic) twins are found to have higher concordance rates than non-identical (dizygotic) twins – for musical ability, schizophrenia, love of romantic films or whatever – this would suggest a genetic basis. This is because MZ twins share 100% of each other’s genes, whilst DZ twins share about 50% (the same as any siblings).
Genotype and Phenotype
A person’s genotype is their actual genetic makeup, whereas phenotype is the way that genes are expressed through physical, behavioural and psychological characteristics. The expression of a genotype is inevitably influenced by environmental factors. For instance, identical adult twins usually look slightly different because one has exercised more or one has dyed their hair and so on. So, despite having the same genes, the way identical twins’ genes are expressed (the phenotype) is different – see also the example of PKU (opposite). This illustrates what many biological psychologists would accept, that much of human behaviour depends upon an interaction between inherited factors (nature) and the environment (nurture).
Evolution and Behaviour
The evolution of animals and plants is a fact. In the 19th century, Charles Darwin proposed a theory to explain this fact – the theory of natural selection. The main principle of this theory is that any genetically determined behaviour that enhances an individual’s survival (and reproduction) will continue in future generations, i.e. be naturally selected. This happens in a similar way to a farmer deciding which animals to use for breeding – the farmer selects the ones who possess desirable characteristics. For example, if one of a farmer’s cows has a high milk yield the farmer chooses this cow for further breeding so his stock of cows become progressively better milk producers. In nature this selection takes place ‘naturally’ – no one ‘decides’, the selection occurs simply because some traits give the possessor certain advantages. The possessor is more likely to survive, reproduce and pass on these traits. If the individual survives but does not reproduce, the traits do not remain in the gene pool.
