twin studies as a research method

• Twin studies are a way to investigate the effects of nature and nurture on behaviour. Nature refers to biological causes for behaviour: in general, twin studies investigate the role of nature (genes). Nurture refers to the environmental causes of behaviour: this means the importance of upbringing, regardless of who the parents are.
• Twin studies are measured using a statistic called a concordance rate. Concordance means “agreement”, so if one twin shows behaviour and the other twin does too, this is concordance. 100% concordance means all the twins shared the behaviour or characteristic. 0% concordance means none of them shared the behaviour or characteristic. In a twin study, the concordance rate of the MZ twins is compared to that of the DZ twins.
• + researchers are able to easily see if there is a genetic component. If the concordance rate for MZ is greater than the concordance rate for DZ the only difference is the number of shared genes so this must be the factor.
• • MZ twins are often treated more similarly than DZ twins therefore the environmental experience of MZ twins is more intertwines and therefore a shared environment influencing higher concordance rates is difficult to discount.