Nature Vs Nurture: Collaborating to Shape Human Behavior

The discussion of role that an individual’s genetics play in their personality and development has been debated for decades. The question of nature versus nurture is at the heart of behavioral genetics. Nature involves the natural variations in brain structures and unique personality traits that are inherited. On the other hand, nurture involves the influence of factors outside of an individual’s genetic makeup, such as: family, culture, and traumatic experiences. However, some naturally occurring genes are activated through certain environmental factors.

A researcher from the University of Queensland collaborated with VU University of Amsterdam to examine twin studies across the world since the 1960s, involving approximately 14.5 million pairs of twin subjects. The results, published in Nature Genetics, demonstrate that genetics contribute 49 percent of the average variation for traits and diseases and 51 percent was influenced by environmental factors. The findings revealed that researchers should view it as nature and nurture instead of nature versus nurture.

Although environmental factors commonly influence personality traits independently of genes, genetic and environmental factors are often closely interlinked. In some instances, the environment alters a gene’s DNA sequence of activity level. Phenotypic plasticity refers to a specific genotype being able to produce different phenotypes in response to different environmental factors. This often impacts an individual’s physical health, for example, UV radiation can disrupt DNA strands and lead to higher risks of melanoma. However, recent studies have discovered that certain environmental factors can cause a change in the epigenome, the chemical tags attached to DNA. The epigenome determines the activity level of certain genes and refines the amount of protein created in an individual’s body. Factors such as diet, stress, and social experiences can all have potential effects on an individual’s epigenome. Specifically, early exposure to social experiences and a positive childhood growth environment can have significant and permanent benefits on one’s personality traits. Environmental factors often influence one another and the interactions between different factors are highly complex. Scientists continue to investigate the interconnected relationships between certain environmental factors and personal development.

The 2018 documentary Three Identical Strangers directed by Tim Wardle is a timely representation of the surprising ways that genes and the environment interact to shape individuals. The film captures a story about identical triplets born in 1961 and adopted into different families. The era in which the children were born (the 1950s and 60s) was known as the Wild West of psychology, where people pushed the boundaries on psychological investigations. Psychiatrist Dr. Peter B. Neubauner used these children as guinea pigs for his research in attempting to uncover the mystery of nature vs. nurture. The study was performed as part of a scientific “nature versus nurture” twin study that aimed to follow the development of genetically identical siblings raised in different family circumstances. The three siblings were intentionally placed into families of different social classes and parenting styles - blue-collar, middle-class, and affluent. When the three subjects of the documentary were reunited years later, they not only looked identical but shared a number of habits. Despite their differing family economic status, they had the same interests, smoke the same brand of cigarette, liked the same type of girls, and had the same sitting position. “They were more like clones than brothers.”

Unfortunately, in 1995 one of the triplets, Eddy Galland who had exhibited signs of bipolar disorder, committed suicide with a gun. The audience is forced to question the reason behind Eddy’s mental illness and whether it was inherited from their biological mother who also experienced psychological disorders or influenced by the environment he grew up in. The results of this study have never been published as the files recording the answers are locked up in Yale University and will only be released in 2066. The public is left with questions about not only the topic of nature versus nurture but more significantly the ethics behind the investigation.

The study of each of the components of the equation of heredity and environment and their effects on shaping one’s development and traits has demonstrated that nature and nurture are complementary and collaborate to shape human behavior.

Reference List

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