Is the mind inherited?
We are now at a historical turning point in the field of genetics. In fact, one can think of it in terms of "Before Chromosome" and "Anno DNA" in that it constitutes a historical divide similar to the way in which historical time is categorized as either "Before Christ" (B.C.) or "Anno Domini" (A.D). People now recognize the importance of heredity and its influence of physical characteristics and disease.
However, even today, it seems that many people consider the human mind and behavior to be unrelated to heredity. The Pope agrees that humankind is an evolutionary product and thereby recognizes the theory of evolution, but even in this case, however, he qualifies this acceptance with the assertion that the human spirit is not subject to evolution. In this way, the human mind is still considered to be the last stronghold.
However, proof is better than argument. In my lectures, I use a study on identical twins to teach my students that people's mind is actually very much affected by heredity. First, I show them a video indicating that identical twins behave very similarly, implying that their minds and behavior are subject to the influence of heredity. As a scientific complement, I also introduce the so-called, Twin Method to statistically compare similarities between identical and fraternal twins.
Given the mind and body are the genetic outcomes, it is understandable that the body and mind would be more or less influenced by heredity. My students may feel very uncomfortable when they hear this. To them, heredity implies destiny. This sort of simplistic view of heredity is very deep-rooted.
A simplistic view of heredity probably comprises several ideas: the idea that traits are transmitted from parents to children, the notion that one's nature is fixed and never changes throughout life; the notion that the nature remains unchanged regardless of environmental changes, and so on. These ideas lead to a fatalistic pessimism that one can do nothing because heredity is destiny.
I share many stories with my students that overturn such a simplistic view of heredity. First of all, I tell them that no two people have exactly the same set of genes. Everybody is different. Second, I talk about the genetic mechanisms and the effect of genes. The basic mechanism of sexual reproduction is to make a new set of genes different from one's parents through gene reshuffling. Heredity is therefore better defined as a mechanism to create a genetic makeup different from the parents. Heredity often reminds us of the similarity between parents and children, as in "like father, like son." However, it also causes dissimilarity between parents and children as in the Japanese saying "A kite breeding a hawk", in English "A black hen lays a white egg."
In the days when intelligence was believed to be genetic and unchangeable, people had an idea that people born with high level of intelligence would retain that level throughout life and that those with low level of intelligence at the start of life would remain the same. This belief is based on a notion of unchangeable destiny. However, a developmental curve of one's intelligence is rather inconsistent. The developmental curve of each identical or fraternal twin shows ups and downs, with the gap between high and low scores as much as 30 or 40 points. In this context, the level of intelligence is never the same all throughout one's life. The shapes of developmental curves are, however, more similar among identical twins.
With regard to the relationship of the environment and heredity, I often tell my students about a study that assesses and verifies children's adaptability to a certain situation. In one situation, children's behavior is controlled and in the other, they are allowed to play as they wish. The free playing session shows a higher rate of genetic transmission. Genetic traits do not necessarily appear in the same manner all the time; they are expressed in different degrees depending on the environment.
Humans as a Genetic Existence
After all, genes are the building blocks of life, not the determining factors. The word "gene" derives from the Latin word meaning, "to make, produce, create." In Japanese it is "Idenshi", elements that are kept and transmitted, strongly implying the sense of succession. In China it is written with the characters meaning "basic factor." What is important is the idea that genes make up the body and are the building blocks that create the human; they are not elements that control human beings from the outside.
Having studied behavioral genetics for almost 20 years, I have come to understand in my own way how heredity influences human behavior. Nevertheless, I am also struck by how increasingly difficult it is to understand human beings despite the exciting new developments taking place in genetics every day.
How can we obtain a clear picture of the genetic existence of human beings? Behavioral genetics today may lack sufficient tools for that purpose. However, by viewing human beings from the study of children and related perspectives as a kind of filter, we may be able to gain a perspective on living. When invited to join the Study Room on Child Science, I did not know at first how I should position my research and even now I am trying to find a way to do so, but I believe that this is a good opportunity for me to return to the starting point of my studies in heredity that I began as research in the field of education.
We are now at a historical turning point in the field of genetics. In fact, one can think of it in terms of "Before Chromosome" and "Anno DNA" in that it constitutes a historical divide similar to the way in which historical time is categorized as either "Before Christ" (B.C.) or "Anno Domini" (A.D). People now recognize the importance of heredity and its influence of physical characteristics and disease.
However, even today, it seems that many people consider the human mind and behavior to be unrelated to heredity. The Pope agrees that humankind is an evolutionary product and thereby recognizes the theory of evolution, but even in this case, however, he qualifies this acceptance with the assertion that the human spirit is not subject to evolution. In this way, the human mind is still considered to be the last stronghold.
However, proof is better than argument. In my lectures, I use a study on identical twins to teach my students that people's mind is actually very much affected by heredity. First, I show them a video indicating that identical twins behave very similarly, implying that their minds and behavior are subject to the influence of heredity. As a scientific complement, I also introduce the so-called, Twin Method to statistically compare similarities between identical and fraternal twins.
Given the mind and body are the genetic outcomes, it is understandable that the body and mind would be more or less influenced by heredity. My students may feel very uncomfortable when they hear this. To them, heredity implies destiny. This sort of simplistic view of heredity is very deep-rooted.
A simplistic view of heredity probably comprises several ideas: the idea that traits are transmitted from parents to children, the notion that one's nature is fixed and never changes throughout life; the notion that the nature remains unchanged regardless of environmental changes, and so on. These ideas lead to a fatalistic pessimism that one can do nothing because heredity is destiny.
I share many stories with my students that overturn such a simplistic view of heredity. First of all, I tell them that no two people have exactly the same set of genes. Everybody is different. Second, I talk about the genetic mechanisms and the effect of genes. The basic mechanism of sexual reproduction is to make a new set of genes different from one's parents through gene reshuffling. Heredity is therefore better defined as a mechanism to create a genetic makeup different from the parents. Heredity often reminds us of the similarity between parents and children, as in "like father, like son." However, it also causes dissimilarity between parents and children as in the Japanese saying "A kite breeding a hawk", in English "A black hen lays a white egg."
In the days when intelligence was believed to be genetic and unchangeable, people had an idea that people born with high level of intelligence would retain that level throughout life and that those with low level of intelligence at the start of life would remain the same. This belief is based on a notion of unchangeable destiny. However, a developmental curve of one's intelligence is rather inconsistent. The developmental curve of each identical or fraternal twin shows ups and downs, with the gap between high and low scores as much as 30 or 40 points. In this context, the level of intelligence is never the same all throughout one's life. The shapes of developmental curves are, however, more similar among identical twins.
With regard to the relationship of the environment and heredity, I often tell my students about a study that assesses and verifies children's adaptability to a certain situation. In one situation, children's behavior is controlled and in the other, they are allowed to play as they wish. The free playing session shows a higher rate of genetic transmission. Genetic traits do not necessarily appear in the same manner all the time; they are expressed in different degrees depending on the environment.
Humans as a Genetic Existence
After all, genes are the building blocks of life, not the determining factors. The word "gene" derives from the Latin word meaning, "to make, produce, create." In Japanese it is "Idenshi", elements that are kept and transmitted, strongly implying the sense of succession. In China it is written with the characters meaning "basic factor." What is important is the idea that genes make up the body and are the building blocks that create the human; they are not elements that control human beings from the outside.
Having studied behavioral genetics for almost 20 years, I have come to understand in my own way how heredity influences human behavior. Nevertheless, I am also struck by how increasingly difficult it is to understand human beings despite the exciting new developments taking place in genetics every day.
How can we obtain a clear picture of the genetic existence of human beings? Behavioral genetics today may lack sufficient tools for that purpose. However, by viewing human beings from the study of children and related perspectives as a kind of filter, we may be able to gain a perspective on living. When invited to join the Study Room on Child Science, I did not know at first how I should position my research and even now I am trying to find a way to do so, but I believe that this is a good opportunity for me to return to the starting point of my studies in heredity that I began as research in the field of education.
