Nature Versus Nurture

Nature versus nurture is a very old debate, which argues what forces shape human behaviour more, genetics or the environment. Supporters of the nature theory of human behaviour believe that genetics is more powerful in shaping personal behaviours or development of culture than the environment is. They believe human behaviour is innate or instinctual. No matter what type of environment or family the individual is raised in he or she will turn out the same, because human behaviour is ‘wired in'. The argument against this theory is that people all over the world would behave the same, yet anthropological data would dispute this. For those that believe in the nurture theory of human behaviour they believe humans are born as blank slates, and the experiences throughout their life and their environment shapes their behaviour. This theory believes that people are taught to behave and think in certain ways because they have learned from their families and significant others how to behave.

Scientists interested in the genetics of human behaviour look for patterns of behavioural inheritance and therefore commonly use twins as subjects. The Minnesota Study of Twins Reared Apart, was undertaken by Thomas Bouchard, and is based at the University of Minnesota. The study was started in 1979 and has the largest number of monozygotic and dizygotic twins on registry in the world. Monozygotic twins are twice as similar genetically as dizygotic twins. The idea of twin studies is to look at the variability in behaviour when comparing monozygotic twins raised apart or together with dizygotic twin pairs raised apart or together and then compare these for variability. When large enough studies are performed it is possible to differentiate the genetic influences from environmental influences ‘based on the degree to which the subjects under study share common genetic backgrounds versus common environmental influences' (Clark 2004 p.11). He goes on to say that most of