Essay on Nature vs Nurture: Twin Studies and Adoption
1958 Words8 Pages
The nature- nurture debate has many different case studies, which often questions environmental and hereditary aspects of the nature- nurture debate. A tangent which is focused on in this essay is how the case studies of schizophrenia and IQ, specifically affect twin and adoption studies. This essay will firstly, give a brief outline of the nature-nurture debate and the definitions of twin and adoption studies. Secondly, it will illustrate two main case studies, which are IQ and Schizophrenia studies. Thirdly, will contrast and compare the two and research’s impact on the case studies in regards to nature vs. nurture and finally, will conclude with the impact of the nature-nurture debate and twin and adoption studies.
“The term “nature…show more content…
Extending on from these, factors in each layer are influenced by elements within and outside of their layers. For example what a child is exposed to as a result of his/her parent’s beliefs. (Social Issues Referencing, 2007) Due to these factors, the nature- nurture theory has impacted and influenced many studies, one of these being the twin and adoption case.
Twins, share a bond that no parent, child or sibling relationship can ever compare. There are two main types of twins, and these include: monozygotic (identical) twins and dizygotic (fraternal) twins, and they are compared by their emotional, behavioural, and cognitive similarities. (Robert Plomin, 1997). According to Social Issues Referencing, 2007, whereas Identical twins are formed from a single (mono) zygote and are genetic “carbon copies”, fraternal twins develop from two (di) separate zygotes, as a result of two eggs being fertilized by two sperms independently. (Social Issues Referencing, 2007, para. 8)
Ultimately adoption is “the legal process which permanently transfers all the legal rights and responsibilities of being a parent from the child's birth parents to the adoptive parents”, (Human Services, Community Services, 2009 p. 1) so parents who are not related to the child in any form are adopting the child. In a sense, Twin studies relates to nature, as
The controversy over what determines who we are, whether it is Nature (heredity, our biological make up) or Nurture (our environment) is taking a new shape. Through the past decades, psychologists have developed different theories to explain the characteristics of human-beings; how we feel, think and behave. Usually, these theories were one directional in the nature / nurture question. Today, a new approach to deal with this question is emerging. This new approach finds a middle ground between nature and nurture. The conclusion that nature and nurture are complementary and work hand and hand to shape a behavior (a purposeful and meaningful activity) is not a compromise; it is a result of a vigorous study of each of the components of the equation of heredity and environment and their affects on determining one’s development and behavior. In fact, the more we understand about development and behavior, the more obvious it becomes that nature and nurture are similarly influences rather than determinants, not only singly but also in combination. Here below, I will endeavor to expose the leading theories dealing with the question of nature vs. nurture. I will also try to present the third, new-emerging approach meant to solve the mystery of “What is it that makes us who we are?”
“Our genes made us. We animals exist for their preservation and are nothing more than their throwaway survival machines.” This is what Richard Dawkins states in his book: The Selfish Gene. In his international best seller book, he argues that we are merely a product of our genes and our main purpose in life is to serve the genes, become distribution agents and ensure their proliferation. Before we take any stand to Dawkins’ statement, let us familiarize ourselves with what is meant when the term nature is used. Nature represents what we are born with and cannot control. Our biological make up is determined by the genes we receive from our parents (reside in the 23 pairs of chromosomes, 23 from each parent.) “A gene is a segment of DNA or a sequence of nucleotides in DNA that codes for a functional product,” (Tortora, Microbiology. p. 575.) These genes not only affect our outlook, but also play a significant role in determining our behavior and our well-being. “Through new genetic studies, clinical observation, and research on identical twins and adopted children, we are becoming increasingly aware that many of the human characteristics previously taken for granted as products of childhood rearing and environment are rooted in the genetic matrix.”, (Neubrauer, Peter. p 38) Studies of identical twins reared apart have provided researchers with a lot of clues about the role of heredity in everyday life behavior. Twins (monozygotes) are of extraordinary importance when studying heredity because they share identical copies of genes. An interesting study on twin brothers who were separated at birth and raised in different countries by respective adoptive parents showed that they both kept their lives neat, ‘neat to the point of pathology.’ Their clothes were preened, appointments met precisely on time.
When asked about the reason they felt to be so clean, the first one replied ” My mother. When I was growing up she always kept the house perfectly ordered. She insisted on every little thing returned to its proper place,… I learned from her. What else could I do?” When his twin brother was asked the same question he answered “The reason is quite simple. I’m reacting to my mother, who was an absolute slob.”, (Neubrauer, Peter P 21) In this example, we see a natural preference based on heredity. Both twins blamed their mothers for their behaviors, while none of the mothers required such neatness. Another study on heredity and alcoholism conducted by Goodwin et al. (1973) indicated that adoptees with alcoholic parents were four times more likely to become alcoholics than those without, although there was no such relationship with alcohol misuse in adoptive parents, (Pelle, Stanton. p 2). Even though scientists have only identified 16,000 out of the total 100,000 genes, many psychological diseases are on the verge of being unraveled. Take for instance schizophrenia, a disease characterized by (hallucinations, delusions, flat or inappropriate emotional expression, paranoia and suspiciousness). New findings point out to its relatedness to genetics. Genetic markers for schizophrenia are founded on chromosomes 22, 6, 13, 8 and 9, (De Angelis, Tori. Boston globe.) These examples reveal the genetic role in our development. They also expose our predisposition to certain traits and behaviors.
The second camp sitting on the other side of the fence is the advocates for nurture. Here, nurture represents our surrounding: parents, class-mates, colleagues, our value system and our society as a whole. People in this camp argue that man is a product of his environment. Some extremists went as far as saying: give us any new born infant and we will shape him/her just the way we want, by placing him/her in the desired environment. ” As one grows from infancy to adulthood, social experience plays a critical and constant role in the regulation of growth , behavior and emotions,” (Glick, Marion E.) Here we are told that social deprivation at different stages of development can lead to abnormalities in the stress hormone system, which may produce severe and long-lasting physical, neural and psychological consequences. It is also interesting to consider the gender differences due to the change in environment. Few decades ago, women were considered inferior to men in their achievements. Today, even though the misconception of gender roles in society is still present, we can clearly see the gap between men and women narrowing due to the change in environment. The new school emerging to help bring the nature nurture argument to rest professes that there is no war between nature and nurture. Indeed, such war would be absurd because it is the interaction of nature and nurture that defines our behavior and well-being. Here, a question as ” WHY DID YOU STEEL THE CAR? “, cannot be answered by: THE DEVIL MADE ME DO IT, or better yet, MY GENES MADE ME DO IT. In understanding a behavior, both nature and nurture are taken to consideration.
“Moreover, it is perfectly obvious that human social life is related to human biology…Of course, neither biological nor cultural determinists ever wish entirely to exclude the significance of the other.” (R.C Lewontin. p.267-268.) Many psychological illnesses can be explained as a result of combined genetics and environmental factors. As already stated in this paper, schizophrenia has genetic basis. It is also a fact that this mental disease is triggered by environmental factors including family factors and external stress. Paul Grobstein, in his article”Genes, Environments, and Individual Choice” explains that “In human development and behavior, as in the development and behavior of all other living organisms, the genome and the environment instead productively interact with one another, both contributing unique and valuable information to the emergence of distinctive individuals” It is also noteworthy to mention that no two individuals are the same. Not even monozygotic twins have the same environment. “Every person is a unique and non recurrent”, (Dobzhansky, Theodosius. p.8) In sum, in this paper we can conclude that our development and behavior are products of the interaction between nature and nurture. Scientists confirm that we are predisposed to certain traits and behaviors, but this predisposition is susceptible to modification by genetics as well as environmental factors. We can no longer dwell on the question “Is it Nature or Nurture That Determines Who We Are?” We learn that it is this combination of these two vital factors that shape and define our development and behavior.
- Dangles, Tori.” Chromosomes contain clues on schizophrenia”, Boston Globe, Feb17-97
- Dobzhansky,Theodosius. Genetic Diversity & Human Equality.1973
- Glick, Marion E.” Behavior and the Brain:A New View of the Nature-Nurture Debate.” Online. Internet.http//:www.rockefeller.edu/pubinfo/neurolecutre.nr.html. Feb.6.1996
- Neubauer, Peter. Nature’s Thumbprint,1990 Pelle, Stanton.Online.Internet.http://www.frw.uva.nl/acd/isg/drugs/peele/lib/genetics.html.%20Feb.17-97%205:00PM R.C. Lewontin. Not In Our Genes. 1984
- Richard, Dawkins. Selfish Gene, 2nd.edition.1989
- Tortora, Gerald. Microbiology An Introduction, 5th. edition.1995