Nature vs. nurture: How do we understand the interplay between innate genes and acquired environment?

The debate over the influence of genes and environment has historically been characterized by a variety of failures, illustrating the problem with extreme approaches. We need to recognize that both innate and acquired factors play complementary roles in shaping character.

 

The question of “nature or nurture” has been a controversial one since anthropologist Francis Golton first addressed it. Nature refers to innate, inborn tendencies, such as genes, while nurture refers to a whole range of acquired influences that go beyond just parental influence. The debate is still ongoing between nativists, who believe that human behavior is related to genes, and empiricists, who argue that experience and environment are more important. But neither side is completely wrong, because the question is not black and white. There are valid points on both sides, and extreme conclusions are dangerous. If everything is innate due to genes, then ethics and moral education become irrelevant, and if everything is caused by environment and experience, then it is possible to completely modify humans regardless of their natural brain or physical condition. And if we’re trying to compare the contributions of either side of this debate, the question is futile and meaningless, since we can’t definitively separate the two. Therefore, instead of seeing nature and nurture as opposites, we should see them as complementary concepts that contribute to the diversity of humanity by influencing each other in the formation of character. The idea that we are born with a blank slate or that everything is set in stone is overly extreme, and in fact, the role of genes and the environment in which we grow up shows that it is not an either/or proposition.
History has shown that both extreme theories of nativism and empiricism have ultimately failed. First, there’s prenatalism, or “genetic determinism,” which advocates an inborn component, and the extreme version of this is the eugenics of Nazism. It was an argument based on social Darwinism, or “natural selection,” in which inferior genes would be culled. Hitler believed that Jews and Gypsies had inferior genes, so he used “natural selection” to indiscriminately exterminate them. The idea of eugenics was to prevent the growth of a population with inferior genes. In contrast to Hitler, the other extreme of eugenics is found in communism. It stems from the idea that a person’s innate selfishness can be acquired and improved. However, communism was too idealistic to ignore both genetic genius and selfishness, and people were unable to hide their greed and complained about communism. In the end, it failed, just like Nazism. So history shows that it’s not right to argue for either extreme, nature or nurture.
Believing that everything is in your genes is an overly deterministic argument. It’s true that genes do play a role in allergies and constitution, and they do shape personality. However, as important as innate factors are, we must also take into account acquired factors. This genetic determinism can be refuted by neurocognitive science. Our behavior and thoughts are closely linked to the development of our brains, and our neural networks are more acquired than innate. Neural networks are developed by constantly stimulating nerve cells throughout life, which changes their structure. If this stimulation is lacking at an early age, the development of the brain will stagnate, affecting personality and character. In other words, even if a person is naturally talented, he or she often fails to shine if the environment is not created. In addition, after the human genome project, it is difficult to believe that nature has an absolute influence. According to genetic determinism, the number of human genes is far too small (about 30,000, which is not much different from fruit flies), and the environment has a great influence on human diversity. Therefore, it is difficult to believe that genes explain human diversity or personality.
Empiricism argues that genes have a negligible effect on human diversity compared to experience, which can be refuted by the problem of language acquisition. Empiricism was first articulated by the 17th-century philosopher John Locke, who argued that we are born with a blank slate, but the process of language acquisition shows that there are definitely innate qualities. According to the work of renowned linguist Noam Chomsky, people have a universal linguistic capacity that allows them to understand language. Rather than acquiring grammar through acquired effort, the brain has an innate linguistic apparatus that helps us acquire language. This is supported by the fact that universal grammatical structures are found in children who speak different languages, and that there is a critical period when it is easiest to acquire a language. In other words, language is acquired by the universal grammar that children already have, not by learning from scratch. Therefore, in addition to experiential and environmental factors, innate factors also influence people.
The more similar the congenital factors are, the more important the acquired factors become, and conversely, the more similar the environment is, the more important the genetic factors become. This bolsters the argument that genes and environment are complementary. First, we can see that the more equal a society is, the more important the innate factors become. Education is one example. Unlike South Korea, where private education is the norm, most developed countries offer free and equal public education, but students’ math skills vary widely. In other words, genes become an important factor in creating diversity when people are placed in the same environment. Conversely, the more similar the genes are, the more important the acquired environment becomes. If one of the identical twins grew up in a happy, stable family and the other in a violent one, their personalities and tendencies will be very different depending on the environment they grew up in. Identical twins are born with nearly identical DNA, but as they grow up and are exposed to different environments, they develop epigenetic differences. The epigenetic differences between identical twins at age 3 and identical twins at age 50 are three times greater, showing that even with the same genetic information, there are some acquired differences. In genetics terms, an acquired difference can be caused by a mutation in a gene. The estimated mutation frequency in human cells is about 1/10,000 for a single gene, but humans have about 30,000 genes, so the probability of mutation is quite high, especially depending on the frequency of exposure to radiation or UV. So you can see that environmental factors can make a difference even when genes are the same.
The most important rebuttal to the nature vs. nurture debate is that nature and nurture play different roles in the formation of personality and values, rather than opposing each other. In terms of extroversion, genes seem to play a bigger role, while in terms of values and hobbies, environmental factors seem to play a bigger role. This can be seen in studies of identical twins who have been separated since birth. These twins often didn’t know each other at all and were raised in completely different environments. While they had many similarities, they also had differences.
First of all, genes play a huge role in a person’s IQ and personality. Identical twins were very similar in terms of intelligence and had similar tastes and personality traits. Surprisingly, they didn’t take on the personalities of their adoptive parents, but rather more closely resembled their biological parents. Genes play an important role in our physical appearance, as well as in our mannerisms and outgoing personality. This shows that genes can influence a person’s disposition by defining physical factors. On the other hand, experiences and environmental factors have been found to contribute to the formation of values. Twins were found to follow the religion of the family in which they were raised and to be closer to the values of their adoptive parents than their biological parents. In other words, environmental factors and education play a separate role from genes. And even if you are born with the exact same genes, as mentioned earlier, you are not technically biologically identical due to different epigenetic factors. Therefore, nature and nurture should not be seen as opposites, but rather as influencing each other and helping to shape your personality.
Thus, we can see that nature and nurture are not dichotomous, but interacting factors. As the study of genetics and the study of the acquired environment has progressed, modern scientists have come to recognize that it’s not an either/or proposition, and that both factors play a role in shaping character. Just as genetic information influences IQ and experiences play a big role in building values, nature and nurture rely on each other in the process of building a person’s character. It’s no longer a nature-versus-nurture debate, but a nature-via-nurture debate, because when nature is similar, nurture becomes more important, and when nurture is similar, nature becomes more important. This will avoid the political and social ills of eugenics that come from deterministic thinking. Although not yet fully understood, it is clear that the complementary concepts of nature and nurture have great power in analyzing human behavior and thought. If we can understand how and to what extent these two concepts interact, our understanding of human diversity and personality formation will be greatly enhanced.