The study is based on identical twins with the same genetic structure. They came out with the hypothesis that if the environment is responsible for individual differences, then MZT twins who shared the same environment should be significantly more similar than MZA twins. They are called monozygotic twins because they start as a fertilized egg, called a zygote, and then split into two identical embryos. Fraternal twins are the result of two separate eggs fertilized by two separate sperm cells and are referred to as dizygotic twins. …show more content…
The friends, relatives or the reunited twins themselves, contact the Minnesota Center for Twin and Adoption Center (MICTAR). Members of the adoption movement, social workers, and other professionals encounter twins reared apart, serve as a mediator. All twins were tested to ensure that they are monozygotic before beginning their participation in the study.
Participants completed approximately 50 hours of medical and psychological analysis. They used four personality traits inventories, three occupational interest inventories, and two mental capacity battery. Separate examiners handle intelligence test. A comprehensive mental capacity battery is operated as a test group. The twins also complete questionnaires independently, under the constant supervision of a staff