The nature- nurture debate has many different case studies, which often questions environmental and hereditary aspects of the nature- nurture debate. A tangent which is focused on in this essay is how the case studies of schizophrenia and IQ, specifically affect twin and adoption studies. This essay will firstly, give a brief outline of the nature-nurture debate and the definitions of twin and adoption studies. Secondly, it will illustrate two main case studies, which are IQ and Schizophrenia studies. Thirdly, will contrast and compare the two and research’s impact on the case studies in regards to nature vs. nurture and finally, will conclude with the impact of the nature-nurture debate and twin and adoption studies.
“The term “nature versus nurture” is used to refer to a long-running scientific debate. The source of debate is the question of which has a greater influence on development: someone's innate characteristics provided by genetics, or someone's environment. In fact, the nature versus nurture debate has been largely termed obsolete by many researchers, because both innate characteristics and environment play a huge role in development, and they often intersect”. (Smith, 2010 p. 1)
Nature, which is also known as hereditary, is the genetic makeup (DNA) that an individual carries from birth until death. Hereditary characteristics are different in each individual, group and humans in comparison to other species. Nurture on the other hand refers to environmental factors and similar to nature, an individual is also exposed from birth until death. These factors involve elements such as physical environments (prenatal nutrition) and social environments (media and peer pressure). (Social Issues Referencing, 2007)
Similar to nature, environmental factors vary from each person. These factors also involve a range of layered forces from most immediate (family), to larger contexts (local governments) and finally macro factors (e.g., international politics and global warming). Extending on from these, factors in each layer are influenced by elements within and outside of their layers. For example what a child is exposed to as a result of his/her parent’s beliefs. (Social Issues Referencing, 2007) Due to these factors, the nature- nurture theory has impacted and influenced many studies, one of these being the twin and adoption case.
Twins, share a bond that no parent, child or sibling relationship can ever compare. There are two main types of twins, and these include: monozygotic (identical) twins and dizygotic (fraternal) twins, and they are compared by their emotional, behavioural, and cognitive similarities. (Robert Plomin, 1997). According to Social Issues Referencing, 2007, whereas Identical twins are formed from a single (mono) zygote and are genetic “carbon copies”, fraternal twins develop from two (di) separate zygotes, as a result of two eggs being fertilized by two sperms independently. (Social Issues Referencing, 2007, para. 8)