There are many things that form a personality. Psychologists have been trying to analyze and define it for years, trying to figure out what influences it and if it changes over time. One of the things I thought most interesting is how a personality is determined. Is it genes or environment that causes someone to act the way they do? The result surprised me.
According to the Minnesota Twins study, performed right here at the U of M and spanning two decades, it doesn't matter where one is raised. Their personality is based primarily on genes. The study was as follows: two groups of twins were formed, and in one group, the twins would be raised together, in the same household. The other group's twins would be separated at birth and raised in different households. All of the twins would later be given an extensive personality test and the results compared between the twins raised together and those raised apart, to see if there was any drastic differences in personalities. The answer? The twins raised apart had about the same differences in personality as the twins raised together, pointing to a genetic origin of personality, as opposed to an environmental origin.
But just because their personalities are similar doesn't mean they will act in similar manners. In 1933, a set of identical twins was separated at birth. Their personalities turned out to be very similar in the end, but one of them was raised in a Jewish household and one was raised in a Nazi German household. Their political attitudes are radically different, which I find fascinating. This shows that environment does have some influence on personal views, even though one's personality may stay the same.