• Choose a category
• All
• Classic-Fiction

By Root 609 0

Following the Renaissance, the movement toward empiricism brought us philosophers such as John Locke and René Descartes, who proposed that our ideas come to us through experience. Thus, the concept of nurture began. The pendulum of scientific thought swung so far in this direction that psychologists of the late nineteenth and early twentieth centuries claimed that a person’s behavior could be entirely explained by environmental influences. Like Pavlovian dogs trained to salivate at the sound of a bell, personality was considered to be solely a person’s conditioned response to their unique environment. Around the same time, modern understanding of Mendelian genetics provided empirical evidence for the heritability of traits, invigorating the argument that our identity is predetermined—the exclusive product of nature. Since then, there has been continual debate about which is more important in explaining who we become—nature or nurture? These days, the accepted wisdom holds that any understanding of human behavior should account for the influence of both: nature and nurture are not mutually exclusive explanations, but are two coinciding factors that interact to influence our development.

Ultimately, who we become reflects the sum of genetic and environmental influences, even though individual traits may result directly from one or the other. Nature is solely at play in determining our blood type, whereas nurture almost exclusively determines which language we speak. However, the majority of traits fall somewhere in between. For example, we have genes that influence our height, but environmental factors control how those genes will be expressed. The average person is now several inches taller today than a century ago. Even though our genes are not drastically different from our ancestors’, improved safety, health care, and diet have enabled increased growth in modern humans. This succinctly reflects the current understanding of how we become who we are: nature via nurture. We inherit a set of traits, but our environment determines how those traits are expressed. Although alcoholism runs in families, not all children of alcoholics will grow up to be drinkers. However, when exposed to the same environment, alcoholics’ children are at a greater risk of alcohol dependence compared to a child without a family history of alcoholism.

The primary method used to understand the relative role of nature and nurture is twin studies. Identical twins share all their genes, whereas fraternal twins share roughly half of them. If the trait you are studying is hair color, you would expect all identical twins, but only about half of fraternal twins, to have the same hair color. Hair color is highly heritable: sharing the same genes means you always have the same hair color. This logic applies equally for personality traits as it does for physical characteristics. If fraternal twins share a personality trait only half as often as identical twins, it indicates that the trait is highly influenced by nature and minimally influenced by nurture. However, if both fraternal and identical twins share the trait 70 percent of the time, it indicates that the trait must be highly influenced by nurture and minimally influenced by nature.

Creating a Monster

What does this tell us about Dexter? Are psychopaths born or made? Research has consistently confirmed that nature and nurture each account for about 50 percent of the risk for developing antisocial behavior.6 However, certain genetically inherited traits, such as callousness, are closely linked with antisocial behavior and can augment the risk of developing conduct problems. Using knowledge of behavioral genetics and antisocial behavior, we can try to dissect Dexter’s character to determine what nature and nurture contribute individually and how the two interact to create his persona.

One of the inherent problems with most nature/nurture case studies is that the people who give children their genes, the parents, are usually the same people who give children their environment. Does a boy grow up