: Evidence has suggested that if one identical twin (monozygotic [MZ], with near-identical genetic information to the other) develops schizophrenia, there is a roughly 48% chance of the other also developing schizophrenia, whereas this is only about 17% with non-identical twins (dizygotic [DZ], who share about 50% of their genes).
Such findings support that genetics play a significant part in the disorder.
For example, cortisol and adrenaline are key hormones that facilitate the fight or flight response, a key evolutionary survival mechanism whereby the body primes itself for imminent danger (e.g.
increasing heart rate, initiating sweating to cool down, dilation of pupils, sharpened sense of hearing).
Interactions between regions of the brain help to control different functions, which biological psychologists assume to be significant in determining our actions.
For instance, the occipital lobe is involved heavily in processing sight, along with the frontal lobe, which is thought to be involved in control and attention.Charles Darwin’s publication – On the Origin of Species (1859) – described the process of natural selection; characteristics that are not suited to a species’ environment will die out as it struggles to survive, and with time will evolve over generations so that only adaptive characteristics remain in future offspring.Genes are the genetic information carried by DNA in chromosomes, found within a cell’s nucleus; they are passed on through generations of a species if individuals survive and successfully reproduce.Weaknesses - The approach is considered reductionist; complex behaviour, thoughts and emotions are all equally explained by low-level biological mechanisms such as biochemicals and nerve impulses.- Biology alone has been unable to explain the phenomenon of consciousness.The genotype describes the genetic configuration of an individual, whereas phenotype describes the effects of genetic makeup and surrounding environment on behaviour.The nature-nurture debate highlights a key argument in psychology, over the relative influence of biology and environment on the characteristics of an individual; an extreme biological approach assumes that these are determined solely by nature.Strengths - Scanning research techniques are useful for investigating the functions of the brain: an organ with obvious involvement in our behaviour that would otherwise be unobservable.- The approach presents the strong nature viewpoint of the nature-nurture debate.Case studies – can investigate normal behaviour by observing behavioural abnormality alongside corresponding changes in biology.A very early example is the apparent personality alteration observed in Phineas Gage (mid 1800s) after a railroad construction accident drastically changed his physiology by forcing an iron rod through his brain’s frontal lobe.