Nature or nurture: which is more important in shaping human character?

The debate over whether nature or nurture is more important in the formation of human beings is not easily concluded, as genes and environment interact with each other to shape us.

 

The question of how humans are made has been around for a long time. Thanks to advances in science and technology, these questions are gradually being answered. Starting with Watson and Crick’s discovery of the double helix structure of DNA, DNA is slowly being sequenced, and genes are being studied. Initially, it was thought that genes only determined physical features, but as time went on, more and more scientists began to think that genes were also involved in the formation of human personality. The debate over the formation of human character began to intensify when Francis Golton first coined the phrase “nature versus nurture”.
Those who believe that nature is more important in shaping a person’s character say that genes cannot be changed. They believe that genes control not only our physical features, but also our emotions and behaviors. People with these views came together to formulate a theory, which evolved into genetic determinism. Genetic determinism is the view that an organism’s behavior is the inevitable result of the sum of its genes. It considers genes to be the most fundamental essence of an organism and argues that human social behavior is also determined by genes. According to this theory, genetic studies can tell us everything about how an organism will behave, what diseases it will get, and what it will look like. As the study of DNA became more advanced, the number of proponents of genetic determinism grew, and scientists thought that by unlocking the secrets of genes, they could unlock the secrets of human formation. The proponents of genetic determinism immediately embarked on the Human Genome Project, an effort to find and catalog every gene in the human body. This idea stemmed from reductionism, which is the idea that complex phenomena can be analyzed by reducing them to simpler ones, i.e., by reducing larger units to smaller ones. Modern biology was built on this reductionism. As science progresses, scientists tend to analyze all phenomena in a reductionist way. In biology, scientists discovered cells, DNA, etc. by analyzing them in smaller and smaller units. This was a great way to do research, but it wasn’t the right way to interpret it. According to the reductionist method, gene expression is a unidirectional process in which smaller units are formed from larger ones. This theory, called the central dogma, asserts that DNA is the primary determinant of the properties of proteins, with a one-way transfer of information from DNA to proteins.
However, the findings of the Human Genome Project pointed in a completely different direction. According to genetic determinism, humans have an enormous number of proteins, and if you count the genes that regulate the activity of the genes that encode these proteins, there should be at least 120,000 genes in a human chromosome. However, the Genome Project found that humans only have 25,000 genes. In other words, genes don’t control everything about us. Even the most primitive organism, the nematode, has 24,000 genes, and the fruit fly has about 15,000 genes. This means that one gene does not correspond to one trait. In other words, genes don’t determine everything about us. Therefore, something other than genes, or nature, plays a more important role in shaping us.
Against genetic determinism, a new theory emerged: epigenetics. After the failure of the Human Genome Project, which started with a reductionist method, scientists began to look in a new direction. As a result, they realized that environmental influences can change DNA, or genes. This means that the formation of traits is not unilaterally initiated by DNA, but can be modulated by environmental signals. The activity of genes is regulated by regulatory proteins, and environmental signals regulate regulatory proteins. Studies that have shown that regulatory proteins can create more than 2,000 protein variants from the same gene by modulating the regulatory proteins also support the idea that environmental influences can play a role in shaping humans. Furthermore, genes don’t directly control their own behavior. Instead, it is the effector proteins that act in response to environmental signals picked up by receptors on the cell membrane. In other words, the expression of a gene’s trait is not driven by the gene itself, but is regulated by the surrounding environmental requirements. An experiment that illustrates this is the Agouti gene. The agouti gene is an abnormal gene that causes mice with this gene to have yellow fur and be obese. Mice with this gene were fed a diet that blocked the activity of the gene. The mothers of these mice then had offspring that, although they had the abnormal agouti gene, had chestnut-colored fur and were slim. In other words, the environmental changes experienced by the mothers were passed on to their offspring. The fact that the gene expression was not caused by the environmental factor, food, means that environmental factors can regulate gene expression, which means that genetic determinism, the idea that everything is determined by genes, is wrong.
And we can see that genetic determinism is wrong from historical events. The Nazi Holocaust was caused by eugenics, which was based on genetic determinism. Eugenics is the study of how to socially intervene and perform artificial selection in order to preserve the best genes, based on the premise that there are differences in excellence in genes. In the past, those who believed that genes determined everything believed that human talents and traits were also inherited by genes. This idea was further developed to categorize people with superior genes and those with inferior genes. In the 19th century, eugenics emerged in many countries, and it went further to categorize excellence among races. Differences in the genes of a race were used to categorize superior and inferior races. Eventually, this eugenics in Germany led to the Holocaust, the genocide of the Jews. These events caused eugenicists to rethink eugenics and led to the decline of eugenics. In other words, it turned out that there is no such thing as a superiority order among genes, and that human differences are not related to genetic differences. In other words, nature (genes) does not play a large role in the formation of human beings.
Let’s look at this from the perspective of nurture. The theory that favors nurture in the nature vs. nurture debate is environmental determinism. Environmental determinism argues that the role of the environment is greater than the role of genes in shaping human beings. According to environmental determinism, organisms are not governed by genes, but rather are active agents that change and adapt to their environment. This means that the flow of information is a web of interactions rather than a one-way relationship. In other words, the many factors involved in shaping a human being are interrelated and interact with each other. Recent research has shown that proteins in cells interact with each other under the influence of the external environment. Environmental determinists support epigenetics to emphasize that human formation was shaped by the environment. Epigenetics suggests that environmental factors determine gene expression, which manifests as changes in gene expression rather than changes in genes. Environmental determinism also emphasizes plasticity. Plasticity is the ability of an organism to adapt to the environment in which it lives: the ability of gene expression to change in response to environmental influences.
It is true that genes determine our physical characteristics and behaviors, but they are not fixed in stone and have the potential to change in response to environmental cues. In other words, genetic determinism is a false theory. The assumption that genes are unchangeable is no longer supported by the emergence of epigenetics, which shows that gene expression can be altered by environmental influences. The fact that gene expression can be changed by environmental influences means that the role of environment (nurture) is more important than the role of genes (nature) in the formation of human beings. Human formation is the result of the interaction between nature (genes) and nurture (environment). Genes provide the basic framework for human formation, but environmental factors play a role in shaping and expressing that framework. In human development, genes and environment don’t work in isolation, but rather interact with each other to shape us. An example of this is identical twins. Identical twins have the same genes and look the same. However, if they are raised in different environments, they will have very different personalities. This proves that even if the genes are the same, environmental factors can shape human beings differently. Another example of the importance of the environment in shaping a person is Tiger Woods. Tiger Woods is considered one of the greatest golfers of all time. His natural physical talent is one of the reasons why he became the best golfer he was, but the environment he grew up in also played an important role. Tiger Woods’ father taught him to play golf from a young age and worked hard to nurture his talent. These environmental factors helped him become the best golfer he could be. The environmental factors that nurtured Tiger Woods’ talent played a more important role than his natural genetic talent.
In conclusion, the debate about whether nature or nurture is more important in shaping human beings is not easily concluded. It’s true that genes and environment interact to shape us, but recent research suggests that environmental factors are more important. Genes provide the basic framework for human formation, but it’s the environment that fills in and shapes that framework. Therefore, it’s the environment in which a person lives that matters most, rather than their genes.