Nature, Nurture or Neither: Identical Twins Hold The Answer
There have been many theories that postulate the importance of nature over nurture. For years, many have pondered the question as to whether or not our DNA is chiefly responsible for our behavior, or whether it’s our environment that has more pull on us as individuals. While the answer may be clear depending on with whom you speak, it is decidedly murky in the eyes of many more who seek the truth.
The desire to unlock one of the timeless questions regarding our true selves has led investigators to what appears to be the perfect “control” group: identical twins. Borne of the same fertilized egg which eventually split into two, these particular types of twins appear to hold the secret as to whether or not genetics play a defining role in one’s character…or not.
A recent article discusses the increasing interest and advancements in the field of epigenetics. This growing area of study underscores the hypothesis that it is neither nature nor nurture independently that determines one’s behavior. There is indeed a third factor that may need to be considered in making an absolute determination of cause. Epigenetics serves to act as a bridge between our environment and our genes, shaping who we are in the process.
English scientist Frances Galton first suggested the approach of using twins to measure the influence of heredity in 1875, coining the term “nature and nurture.” Since that time, the idea of identical twins as the beacons of scientific discovery has become of increasing interest, with a new phase of discovery commencing in the 1980’s following numerous revelations of identical twins that had been separated at birth.
Case in point: “The Jim Twins” – Jim Springer and Jim Lewis, identical twins who were separated at birth and put up for adoption. Though raised by two different families, the men shared uncanny similarities that extended beyond their first names. Reconnected at age 39 having never met each other previously, the twins were shocked to learn that they had been living what appeared to be parallel lives, right down to the names of their wives (both first and second marriages), pets and choice of beer. Even while living in different family environments, they shared similarities that seemed too precise to be coincidental. How could this be?
Researcher Thomas Bouchard Jr. looked at the situation with the “Jim Twins” as an opportunity to perhaps reveal the details about “nature or nurture” and invited the twins to his lab in Minneapolis. This was the beginning of what would become an extended and in-depth study on the nature of identical twins, nature, nurture and epigenetics, with over 137 sets of twins passing through Bouchard’s lab. The Minnesota Study of Twins as it was now known subjected its subjects to a battery of tests in an effort to find out how much hereditary vs. the environment played on those with identical genetics. Studying details of human nature such as personality, intelligence and more, this research is classified as a statistical concept called heritability. Generally speaking, the heritability of a trait measures the extent by which differences amongst certain population members can be explained by differences in their genetics.Continued on the next page