There have been many debates in the field of psychology wether we behave the way we do due to nature or nurture. This controversy has many sides to it. Most of the time it can be concluded that they collaborate. But how do behavioural psychologists and geneticist actually find evidence that the genes play any role in our behaviour at all? Psychologist always try to find out what leads a person to a certain behaviour. On the nature side of view, it is depicted that behaviour is generally inherited and in our genes, it just sometimes needs a trigger from the environment. To understand certain kinds of behaviour and to help find the causes of patterns of behaviour, gene studies are important. The more one understands about how behaviour develops the more it is likely to prevent outbursts and mental problems and the easier it will get to predict certain types of behaviour.
In general, it is believed that most personality traits are inherited and therefore genes passed on by the parents and mostly triggered by environmental factors. First of all, one needs to understand what genes are. Genes are, „the unit of hereditary transmission encoded in DNA [...] transmitted from a parent to its offspring“. (as cited in Colman, A. M. (2009), Dictionary of psychology). Each organism has two genes for each characteristic one inherited by each parent.
One example of research that suggests that genetic inheritance contribute to behaviour is inbred strain lines. So far this is has only been tested in animal research. Inbred strain lines are important to genetical research as inbreeding minimises genetic variation. Therefore, the line will be genetically similar. Pearl and Parker (1922), inbred five different strains of fruit flies to investigate their longevity. The resulting age ranges were distinctive and spoke for themselves. Accordingly, genes play a major role in longevity. As genetical inheritance has been proven to be involved in longevity it can be concluded that it is playing a role in other traits as well. (Wickens, A. (2000), Foundations of biopsychology)
Biological psychologists and behavioural geneticists try to explain and investigate the role of genes in behaviour by using, for example, twin, adoption and family studies. In twin and adoption studies researchers investigate wether aspects of behaviour are genetically inherited. This gives them the opportunity to focus on the relative importance of genetics and environmental markers.
Twin studies investigate the similarity of monozygotic twins who have completely identical genes and derive from one egg and dizygotic twins who share half of their genes just like brothers and sisters in terms of the similarity of their personalities. Therefore, it is a natural experiment in which the identical inherited genes of the identical twins can be compared with the genetic information of the fraternal twins. This kind of research is neat? As it can be predicted that if genes influence behaviour, the...