Biological approach - a perspective that emphasises the importance of physical (and physiological) processes in the body such as genetic inheritance and neural (cell) function.
Genes - they make up chromosomes and consist of DNA which codes the physical features of an organism (such as eye colour, height) and physiological features (such as mental disorders, intelligence). Genes are transmitted from parents to offspring, i.e. inherited.
Biological structure - an arrangement or organisation of parts to form an organ, system or living thing.
Neurochemistry - relating to chemicals in the brain that regulate psychological functioning.
Genotype - the particular set of genes that a person possesses.
Phenotype - the way genes are expressed through physical, behavioural and psychological characteristics.
Evolution - the changes in inherited characteristics in a biological population over successive generations.
Concordance rates - the degree to which if one twin has a condition, the other also has it.
Basic assumptions of the biological approach;
1) Human behaviour is strongly influenced by our genetic make-up and our genetic inheritance.
2) An understanding of brain structures and functions can explain both behaviour and thought.
3) Chemical processes in the brain are responsible for psychological functioning and an imbalance can cause certain types of mental disorders, e.g. depression.
4) Humans have evolved biologically and have much in common with other animals especially those close to us, e.g. primates.
The genetic basis of behaviour;
Behaviour geneticists study whether behavioural characteristics, such as intelligence, personality, mental disorders, etc, are inherited in the same way as physical characteristics, such as 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. If identical (monozygotic (MZ)) twins are found to have a higher concordance rate than non-identical (dizygotic (DZ)) twins - for music 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 make-up, whereas phenotype is the way genes are expressed through physical, behavioural and psychological characteristics. This expression 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. This illustrates what many biological psychologists would accept, that much of human behaviour depends upon an interaction between inherited factors (nature) and environment (nurture).
Evolution and behaviour;