In this blog post, we’ll examine the background and key research surrounding the long-standing debate over human nature and nurture through Matt Ridley’s ‘Nature and Nurture’, and explore how genes and the environment interact.
The debate over whether humans are governed by “nature”—that is, genes—or “nurture”—that is, the environment—has persisted for a long time, both in the East and the West. This “chicken-or-egg” style debate has been continuously discussed not only in biology but also in various academic fields such as psychology, anthropology, and sociology. The past 100 years, in particular, have been a period of intense debate on this issue. Notable figures include Charles Darwin, who explained the universality of human nature through evolutionary theory; Francis Galton, Darwin’s cousin who coined the term “eugenics”; Hugo de Vries, who contributed to the development of the laws of inheritance following Mendel; American psychologist William James, who argued that the human mind evolves through biological adaptation just like physical organs; Konrad Lorenz, famous for his imprinting theory—these are some of the leading scientists who argued that “nature” is a crucial factor in shaping human beings. On the opposite side were the authorities of empiricism, who maintained that the human mind is shaped by experience. Ivan Pavlov, the Russian physiologist famous for his theory of conditioned reflexes; John Watson, the American who further developed that theory and founded behaviorist psychology; B. F. Skinner, who carried on that tradition and became famous for his “teaching machine”; Sigmund Freud, who argued that childhood experiences have a decisive influence on the human mind; Franz Boas, a German-born pioneer of cultural anthropology; Émile Durkheim, one of the founders of sociology; and Jean Piaget, who explained developmental processes—these were representative scholars who took the position that human nature and social phenomena cannot be explained by biological factors alone. This debate manifested in its most extreme forms in the ideologies of communism—which advocated for nurture through social reform—and Nazism, which espoused biological determinism.
In response, British science journalist Matt Ridley, in his 2003 book ‘Nature via Nurture’, delves into the roots, background, and evolution of the nature-versus-nurture debate described above, providing a comprehensive overview of its history. This book was later published under the title ‘The Agile Gene: How Nature Turns on Nurture’. Furthermore, the author does not stop at merely introducing the two opposing camps; through fascinating anecdotes and research materials, he presents the numerous studies supporting both sides, as well as innovative attempts to reconcile the two camps. However, simply presenting these facts is not the book’s primary purpose. By presenting and synthesizing these past debates, the author seeks to put an end to the dichotomous thinking that defines human existence as the product of either nature or nurture alone. Ridley previously explored human sociality and morality from the perspectives of genetics and evolution in his earlier work, ‘The Altruistic Gene’, and in ‘Nature vs. Nurture’, he explains in greater detail that nature and nurture are not separate but interact with one another. ‘The Altruistic Gene’ is a Korean translation of Matt Ridley’s ‘The Origins of Virtue’, published in South Korea in 2001. He argues for moving beyond the “nature versus nurture” debate and proposes a new framework of thought: “nature via nurture.” He concludes that while genes dictate the structure of the body and brain in the womb, they simultaneously dismantle or reconfigure what they have created as they interact with the environment. According to him, genes depend on nurture, and nurture depends on genes. In other words, genes are both the cause and the result of behavior.
In fact, even without reading Matt Ridley’s book, one can intuitively understand that both genetics and experience are important in determining certain characteristics, such as a person’s abilities or personality. Of course, depending on the case, some traits are heavily influenced by genetics, while others are heavily influenced by experience and education. However, there are almost no traits determined by the influence of just one factor—either genes or experience.
For example, according to a study cited in this book, when it comes to body weight, identical twins raised in the same household show an 80 percent correlation, whereas fraternal twins raised together show only a 43 percent similarity. Furthermore, the correlation between adopted children and their adoptive parents is 4 percent, and the similarity among siblings is only 1 percent, whereas identical twins raised in different households show a 72 percent similarity in weight. These figures demonstrate that genetic factors have a significant influence on individual differences in weight. However, this does not mean that since your weight is already predetermined, you can eat as much as you want and skip exercise. Even if you have a genetic predisposition to gain weight easily, you can still manage your weight through diet control and exercise. Weight is influenced not only by genes but also by lifestyle habits and the environment.
Research also shows that personality is determined more by genetics than by upbringing. Studies of twins raised apart have revealed the surprising finding that, even when raised in different environments, a significant portion of their personality differences is related to innate factors. This suggests that changes in the home environment do not alter all personality differences. While this conclusion is relatively clear from twin studies, it is also confirmed by research on adoption and on the relationship between twins and adopted children. However, since there are cases where identical twins raised in the same household have personalities that are polar opposites, it cannot be said that genetics alone has a decisive influence on personality.
Research indicates that the influence of genetics on intelligence tends to increase with age. The effect of being raised in a specific environment is strong while the individual remains in that environment but may diminish once that period ends. Studies have reported that while adopted siblings may have similar IQs while growing up together, genetic factors play a greater role in individual differences in intelligence by the time they reach adulthood. In fact, large-scale twin studies have observed that the heritability of general intellectual ability increases as individuals progress from childhood through adolescence and into young adulthood. However, these results should not be interpreted to mean that an individual’s intelligence is fixed by genes; rather, they indicate that the proportion of individual variation within a specific population explained by genetic differences varies with age. Nevertheless, these findings raise the question: if one identical twin were raised in a poor Black neighborhood and the other in a white middle-class household, would their intelligence levels be similar by the time they reached adulthood? Research showing a strong genetic influence does not negate the importance of the environment.
Summarizing these points, the author concludes by presenting seven lessons to be drawn from the nature-versus-nurture debate. Genes are not God; they are cogs in a machine. Do not fear genes. Good parents and a good environment are still important. Personality is the product of attitudes reinforced by desires. Egalitarians emphasize nature, while meritocrats—whom the author calls “snobs”—emphasize nurture. The deeper our understanding of genes and instincts, the less inevitable they become. Social policy must adapt to a world inhabited by diverse individuals. Free will coexists harmoniously with a brain that is superbly pre-programmed by genetics and powered by genes. Furthermore, the author vigorously argues that the nature-versus-nurture debate is not a zero-sum battle but a win-win game in which both sides triumph through mutual complementarity, and he calls for agreement on the compromise outlined above.
“To cook a perfect soufflé, you must not only use the right ingredients but also follow the proper cooking time and sequence.” This sentence, which appears in the book, effectively summarizes Matt Ridley’s views and presents the correct direction for education through a powerful analogy. Just as the freshness and quality of good ingredients are crucial for becoming an outstanding, capable person, it is necessary to possess good genes. However, fresh, high-quality ingredients alone are not enough to create a delicious dish. No matter how good the ingredients are, if you do not follow the proper cooking time and method, the dish will be a failure. The same is true for people. No matter how good your genes may be, if you fail to develop them, it is as if you have thrown good ingredients onto the ground. Therefore, just as important as having good ingredients is the chef who prepares the dish. This means that it is not only important what genes we are born with, but also who raises us and how. Parents and teachers must become excellent chefs capable of bringing out children’s genetic potential. Furthermore, the chef metaphor signifies a balance between nature and nurture, as a chef’s role extends beyond simply producing a delicious dish to bringing out the inherent flavor of the ingredients themselves.
In South Korean society, where excessive nurture theories and distorted environmental determinism are rampant, Ridley’s argument holds significant implications. It is also worth considering what message his remark—that a parent’s most important task is not to shape a child’s permanent traits but to provide care and opportunities—conveys to South Korean parents living in this era. While it may not be possible to say that this book has completely resolved the nature versus nurture debate, it has opened up new possibilities for moving beyond this trite debate by providing fresh insights to help resolve it.
