ARE YOU A “NATURAL?” In 1979, David Lykken and Thomas Bouchard, two geneticists, set out to disprove the common theory of behaviorism which states that all human behavior is controlled by a person’s environment rather than genetics. In other words, they were conducting an experiment to determine which psychological characteristics appear to be determined by genetics and which are molded by environment. In order to conduct this scientific experiment, they had to find sets of identical people which they found in monozygotic twins (identical twins).
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PROCEDURE Each twin underwent 50 hours of testing which included personality scales, aptitude, occupational inventories, intelligence and even checklists on family belongings, resources and environment. They were also required to give life history, psychiatric and sexual history interviews. Each assessment was carried out individually in order to avoid the possibility that one twin could influence the other’s answers.
genetics and environment, the determining factor of who we are is based on the force of either. Another implication of Bouchard and Lykken, is that it is the genetic tendencies in people that mold their environment and even their responses to their environment.
METHOD
RESULTS
In 1983, they began to identify, locate and bring together pairs of these twins. Their sample space included identical twins that were both reared together and separately. As word of the study began to spread, twins or family members and friends of twins, contacted the Minnesota Center for Twin and Adoption Research which is exactly what Lykken and Bouchard needed. All twins were tested to assure that they were identical before they were approved to participate in the study. Each set of twins was then subjected to week-long sessions of intensive physiological tests and measurements. These results were compared with the findings of testing done on identical twins who
CLOSING REMARKS
Logic would say that if environment is responsible for identical people, being different in personality or other characteristics, that twins raised in the same home would be significantly more similar than those twins raised apart. However, this was not the case. In fact, the findings showed that genetically identical humans who were raised in separate and different environments shared extraordinary similar psychological and personality traits. In addition, it was found that the environment had a very small effect on identical twins that were raised together. The study seems to show that although human behavior is a combination of both
Still controversial, this nature vs, nurture experiment, lends itself to a whole new thought process. It is very easy to say that our environment or the way we were raised, determines that kind of person we become. However, when I look at myself in comparison to my siblings who were raised by the same parent in the same environment, I can see the theory that Bouchard and Lykken set out to test. I am very different from my siblings in many ways and yet similar in other ways. I feel as though each person makes different environmental choices based on intellect which is more genetically related. So, maybe they do have something here.