There has been a debate for most of the 20th century over what truly shapes human behavior. Some believe the natural qualities we are born with contribute to how we behave, and what we do with our lives. Others believe that we are a product of our environment, and that our behavior is acquired from what we learn through our surroundings or the environment. Others argue it is a mixture of both nature and nurture that decides human similarities and differences.
It is common knowledge that certain physical traits are inherited based strictly on your individual genetic makeup. "This holds true for traits such as blood type and eye color, but not so for a trait such as height (Glass, 1999)". Height is not determined based on your genetic makeup alone but is also influenced by other environmental conditions. "These conditions vary from one's childhood nutrition to what the conditions in the womb were (Glass, 1999)". .
"Genetic studies currently being conducted are proving that human characteristics once thought of as products of one's childhood rearing are actually rooted in the genetic matrix (Glass, 1999)". Studies have also been conducted on identical twins separated at birth and raised in different homes. These studies show that more often than not the twins will end up living similar lives (Glass, 1999). .
The most famous twin study is the 20 yearlong Minnesota study of Twins Reared Apart (Bouchard et al). This study was conducted on two identical twins reconnected after decades of separation. This study showed the shocking similarities between the .
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twins. Both twins drove the same type of Chevy, smoked the same cigarettes, and both enjoyed stock car racing and football. Even more shocking is the fact that both had married women named Linda, and as children had dogs they both named toy (Glass, 1999). These were not the only similarities either, there were countless other similarities discovered.