Nature vs. Nurture Debate

Nature vs. nurture debate has been the center of discussion for many years. Some believe that human behavior is created naturally while others believe that human behavior evolves over time.

The purpose of this discussion is to discuss both sides of issue and to develop an opinion about which side seems more accurate. Let's begin our discussion by explaining the nature vs. nurture debate.

Nature vs. Nurture

The first recorded experiment concerning nature vs. nurture occurred in the 13th Century. The experiment was conducted by King Frederick II who wanted to see what language a child would pick up if they were not spoken to. He wanted to see if they would just naturally learn language. Steen (1996) asserts that the King was curious as to whether children would teach themselves the Hebrew language, which was the oldest language extant in Europe at the time, or one of the more recent languages such as Greek or Latin. Therefore, he ordered foster mothers to rear and care for a series of children without speaking to them, or exposing them to language in any way. But this experiment was a terrible failure, since all of the children died fairly quickly. Apparently they could not live without the bonding that is fostered through language." (Steen 1996)

Thus one of the oldest debates in the history of the behavioral sciences was born. This experiment made it obvious that nurture shaped the ability of a baby to survive but what was to be said about the impact of nurture on human behavior. The following paragraphs will explain both sides of the issue.

Nature

On the nature side of the debate, is asserted that human behavior is shaped by biological factors including genes and DNA. Individuals on the Nature side of the debate would argue that regardless of parenting or social surroundings human behavior will be determined by biological factors. Francis Galton was among the first to study the phenomenon of nature vs. nurture. One of his first experiments involved the examination of relatives of eminent people. (McClearn and Plomin 1993) This study was published in the volume Hereditary Genius and found that the relatives of eminent people included "a greater number of individuals of high mental ability than could be accounted for by chance."(McClearn and Plomin 1993) Galton also concluded that "nature prevails enormously over nurture when the differences of nurture do not exceed what is commonly to be found among persons of the same rank of society and in the same country." (McClearn and Plomin 1993)

The book asserts that Galton's definition of nature was limited to the confines of the day which meant that when referring to nature Galton was referring to whatever was passed down from generation to generation. (McClearn and Plomin 1993) The authors go on to assert that Galton would have relied heavily upon Darwin's theory of pangenesis to come to his conclusions about nature and human behavior. (McClearn and Plomin 1993)

According to a book entitled, "DNA and Destiny: Nature and Nurture in Human Behavior" there is a biased towards the idea that nature determines human behavior. Steen (1996) asserts that Through most of the history of biology as a science, there has been a subtle but pervasive bias that nature, in the form of hereditary forces at work in the individual, is dominant in the origin of animal traits. Often, by extension, human traits are also seen to result from the unfurling of an immutable program borne in the genes.

The bias toward genetic determinism may have originated with animal breeders, who selected for specific temperaments as well as specific physical traits in domestic animals. But the bias was blessed by science in the era following Darwin and Galton." (Steen 1996)

One of the most pervasive experiments that are usually conducted in the Nature vs. nurture debate involves twins. Twins especially identical twins are used because they have identical genes. Such experiments date back to the late 19th century when the scientist Francis Galton performed experiments using twins as subjects. The book explains that twin studies are one of the two pillars of behavioral genetics. Steen (1996) asserts that many twin experiments have been conducted since Galton's time and many have concluded that much of human variation tends to be inherited.

Book entitled, The Blank Slate: The Modern Denial of Human Nature, discusses the issue of nature and human behavior. In this book the author, Steven Pinker asserts that nature is very likely the factor that determines most human behavior. He explains that naturist have been discredited in recent years. Pinker (2002) argues that there is a quasi-religious theory that strict nurturists use to explain there position. The three components of this theory are; the blank slate, the noble savage, and the Ghost in the machine. (Pinker 2002)

The blank slate component of the aforementioned theory rests on the assertion that people are not born with certain abilities or a certain personality. The Blank slate insists that the behavioral traits that people develop are a result of various social structures including parenting and culture. (Pinker 2002) The noble savage component contends that undesirable behavior in human beings is not inherent and occurs because of social conditioning. (Pinker 2002)The Ghost in the machine factor argues that human behavior is not derived from our biology and that our behaviors can't be traced back to our genealogical lineage. (Pinker 2002)

Pinker also wrote an article in the Boston Globe entitled Sibling Rivalry further explaining his position. In the article he asserts that Behavioral geneticists have done studies that remedy those flaws and have discovered that intelligence, personality, overall happiness, and many other traits are partly (though never completely) heritable. That is, some of the variation in the traits among people in a given culture can be attributed to differences in their genes. The conclusion comes from three different kinds of research, each teasing apart genes and environment in a different way. First, identical twins reared apart (who share their genes but not their family environment) are far more similar to each other than randomly selected pairs of people. Second, identical twins reared together (who share their environment and all their genes) are more similar than fraternal twins reared together (who share their environment but only half their genes). Third, biological siblings reared together (who share their environment and half their genes) are more similar than adoptive siblings (who share their environment but none of their genes)...In each comparison, the more genes a pair of people share (holding environment more or less constant), the more similar they are." (Pinker Oct. 2002)

Pinker also asserts that very little research has proven that a person's environment plays an instrumental role in shaping behavior. More often than not researchers that have conducted the types of experiments listed above have found that a shared environment was not a determinant of human behavior. (Pinker Oct. 2002) He argues that most of these studies have found that adult siblings display similar behavior whether they grew up together or not. (Pinker Oct. 2002) They also found that adopted siblings are as different as two random people from anywhere. (Pinker Oct. 2002) Lastly they found that twins are only as alike as the genes that they share. (Pinker Oct. 2002)

Pinker also points to the assertions made by Judith Rich Harris which contend that nature is the ultimate determinant in human behavior. The author explains that abuse and certain conditions can scar a child but they do not ultimately determine behavior. (Pinker Oct. 2002) Harris asserts that while parents are important and can teach children valuable skills they do not have the ultimate say over their children's intellect or personality because these things are not taught; they are inherent. (Pinker Oct. 2002)

Another book entitled Separate Lives: Why Siblings Are So Different discuses the influence of nature. The book describes brothers that have similar interests but have very different temperaments. This seems to confirm the theory that our personalities, temperaments and intelligence are inherent. The book asserts that, "One reason why brothers and sisters are so different is heredity. The first law of heredity is that relatives are similar and the second law is that relatives are different. This is not just a convenient escape hatch for a weak theory. Rather, it is the essence of the process of inheritance, discovered over a century ago by the monk Gregor Mendel in what is now Czechoslovakia." (Dunn and Plomin 1990)

Mendel conducted many experiments involving traits and inheritance. Through his experiments on inheritance Mendel concluded that inheritance involves two "elements," one from each parent. These elements are discrete and independent -- they do not blend. In addition, he argued, one element can dominate the other in the sense that the dominant element is expressed but the recessive element is not... Mendel's theory is important because it provides the basis for understanding that heredity predicts sibling differences as well as sibling similarities. If blending inheritance were correct, all offspring should be intermediate to their mother and father. Siblings then would not differ. Mendel's theory, however, shows that siblings can be expected to differ in hereditary traits. Because parents each have two elements and offspring inherit one element from each parent, siblings have only a fifty-fifty chance of inheriting the same element." (Dunn, and Plomin 1990)

Nurture

According to DNA and Destiny: Nature and Nurture in Human Behavior, Nurture is defined as the social environment that surrounds and protects the child from birth to independence. This would include early interactions with parents and siblings, as well as the more sporadic interactions with whatever members of the extended family happen to be around. Somewhat later the environment expands to include teachers and friends, and these parts of the social environment assume greater and greater importance with the passing years. Finally, those persons with whom an adolescent or young adult has lasting friendships or love relationships play an increasingly important role, whether those persons are of the same or of the opposite sex. (Steen 1996)

Steen (1996) asserts that nurture is vitally important in sustaining life and determining human behavior. The book asserts that children can be affected by their environments before they are even born. For instance, drug abuse by a pregnant woman can impact the cognitive development of her child. (Steen 1996) Likewise, environmental pollutants can impact the birth weight of a child and the child's physical and mental health. (Steen 1996)

Once a child is born it must be properly nurtured in order to thrive. This means that the child must have a proper diet, attention and love. Nurture is initially given by the parents and family members. The book explains that a mother's interaction with the child is extremely important throughout the life of the child and during infancy. Steen (1996) asserts that Direct interactions between the infant and the mother immediately after birth are extremely important, and the relationship with the mother remains important for the entire life of the child. The personality of the child and that of the mother can interact in a very important way to give this relationship a structure that may last a lifetime. Many neonatal behaviors seem designed to elicit warmth and nurturance from the mother. But if a child is somehow deficient in giving these signals, or if the mother is deficient in receiving these signals, this deficiency can have a major impact on the child. (Steen 1996)

Steen (1996) also contends that the way that a child structures his own environment is important to his development. The author asserts that human beings are constantly structuring their environment and that children are no exception to this rule.

Steen (1996) also points to the ill effects of environmental deprivation. The book asserts that such deprivation can affect human beings ability to develop and get along with others in society. The author explains that environment deprivation can have a negative impact on children as well as adults.

In his book, Ever since Darwin: Reflections in Natural History

Stephen Jay Gould asserts that people that believe that nature is the primary factor that determines human behavior have based these beliefs on the study of animals and not the study of human beings. Gould (1977) asserts that he is not a strict nurturist but instead he believes in the concept of biological potentiality vs. biological determinism. This concept asserts that biological factors play a role in determining human behavior but that nurture can also play a large role in the way people behave. Gould (1977) seems to believe that a strictly naturist point-of-view can not truly be established when discussing human behavior. Gould (1977) contends,

What is the direct evidence for genetic control of specific human social behavior? At the moment, the answer is none whatever. (It would not be impossible, in theory, to gain such evidence by standard, controlled experiments in breeding, but we do not raise people in Drosophila bottles, establish pure lines, or control environments for invariant nurturing.) Sociobiologists must therefore advance indirect arguments based on plausibility... In any case, even if we can compile a list of behavioral traits shared by humans and our closest primate relatives, this does not make a good case for common genetic control. Similar results need not imply similar causes; in fact, evolutionists are so keenly aware of this problem that they have developed a terminology to express it. Similar features due to common genetic ancestry are "homologous"; similarities due to common function, but with different evolutionary histories, are "analogous" (the wings of birds and insects, for example the common ancestor of both groups lacked wings)." (Gould 1977)