For centuries, experts on the science field have argued and debated about which aspect affects human development when it comes to his or her behavior. In this paper, the writer will explain what nature and nurture really means and how the debate about them did begin. Series of researches and case studies by experts will be presented to show how the debate has progressed and evolved through time. There is also an interview included of a female teenager where she will describe as to how she acquired some aspects of her character. The sole reason of the writing of this paper will also be discussed and also, an overall conclusion will be presented.
In psychology, a child’s or a person’s development has always been attributed to two factors – nature and nurture. Nature refers to all the abilities established by genes and present during birth while nurture pertains to experience (Crosbie, 2006). These two are also treated as theories – “nature theory” and “nurture theory” – formulated by two groups of scientists to explain human behavior. One group of scientists believes that humans behave is accordance with their “genetic predisposition” and this includes intelligence, personality, aggression and sexual orientation. On the other hand, the other group of scientists reasons that humans behave based on what other humans taught them to and all the aspects in the environment where one was raised – this includes prenatal environment, brain development, influence of family and friends, and culture (Powell, 2006). Ever since the development of these two theories, the debate has been ongoing about whether nature affects behavior more than nurture or vice versa. However, there are also other views about nature and nurture; some see the relationship of nature and nurture as nature affects nurture and the other way around.
History of the Nature-Nurture Debate
The debate between nature and nurture can be traced all the way back before the 1900s when Plato, the renowned Greek philosopher, alleged that a child already possessed knowledge the moment he or she was born (Crosbie, 2006). None of the other philosophers that were present during Plato’s time contradicted his beliefs – not until the 17th century. Plato’s belief was also assumed by a French philosopher, René Decartes, but was already challenged by an English philosopher, John Locke, argued that a child’s mind at birth does not hold any “innate ideas” because the mind at that point in time can be just compared to a “white paper void of all characters” (Crosbie, 2006).
The argument was triggered more by Charles Darwin’s Theory of Evolution which influenced psychologists like William James in 1890 (Crosbie, 2006). He assumed that humans have natural characteristics that they acquire through “natural selection”. However, James’ statement was challenged by behaviorists, John Watson on 1913 and B. F. Skinner – Father of Behavioral Science, on 1938. Both argued that behavior could only be rationalized through experience; thus, Locke’s argument was recognized as acceptable during the 10th century. Still, there were still those who opposed the said idea like Konrad Lorenz and Niko Tinbergen who, during the 1930s, presented the notion of “instinct” and “critical” period which are both intrinsic attributes of behavior (Crosbie, 2006). In addition, in 1950, Noam Chomsky suggested that every child has an inborn language component within his brains and that language acquisition does not only happen through experience. Along with Chomsky was Cyril Burt who upheld that IQ (Intelligence Quotient) is hereditary.
There have been many researches about human growth and none of them still have determined which between nature and nurture has the greater effect. Researches in psychology about this subject have lead to many conclusions. Psychologists who were greatly influenced by Darwin’s theory – who are called “evolutionary psychologists” – concluded that behavior is an outcome produced by natural selection (Crosbie, 2006). They made use of interpersonal interaction in order to explain their conclusion. According to them, interpersonal interaction is caused by “sexual selection” where both men and women choose partners that can boost their success reproductively. According to a lecture from Wright State University (2002), people choose their partners based on proximity, physical attractiveness and similarities. Men and women differ in their definitions of attractiveness; men want women that look young and healthy so that they are capable of bearing a child while women would like men that look healthy, mature, dominant, bold, and well off so that they are capable of supporting and protecting the family. However, many claimed that the conclusion derived by the evolutionary psychologists is biased and it underestimated the social norms – an aspect which falls under nurture (Wright State University, 2002).
On the other hand, opposite the evolutionary psychologists are the radical psychologists who claim that in order to understand behavior, one should study one’s experience (Crosbie, 2006). Skinner also argued against Chomsky that language acquisition can be rooted to “rewards” and “shaping”. He also proved that human behavior can be shaped like those of the animals when he experimented with pigeons so that they could do figure eights, dance and play tennis (Powell, 2006). Watson also stated that phobias can be understood through “classical conditioning”, and a much recent study claimed that sense of humor is not verified by genes but is only shaped by the environment and the people around the person.
The debate also went to discuss the perception and intelligence aspect. When it comes to the topic of perception, J. J. Gibson, who leaned towards the nature aspect, states that perception is intrinsic to a human because according to his Affordance Theory on 1979, the sensory array of the brain has ample information for perception to occur (Crosbie, 2006). On the other hand, another theory formulated on 1972 by Richard Gregory states that the perceptual process can only be completed by relying on expectation which can be obtained from experiences – a theory which favors nurture. On the context of intelligence, a study on twins and adoption concluded that a huge element of the variation in IQ was mostly cause by genetic factors (Crosbie, 2006). This can also be seen through gene-mapping studies where individual genes that are connected with high IQ were recognized. However, according to Flynn (1987), nurture may also be responsible with the outcome IQ since for over 30 years, IQs all over the world escalated by 20 points (Crosbie, 2006).
However, as time passed by, many authors and psychologists are now discouraging the continuous debate about nature and nurture. According to Pinker (2002), people at the present time would no longer agree that their behavior is being controlled by their genes and that their brain has been blank before and was only filled up with every element that is present in one’s environment. Furthermore, there is already a group that is called “radical moderates” who think that during development, behavior is derived from the interaction of heredity and environment. Some of the beliefs of radical moderates are (1) there are no longer people who believes that a human brain is used to be a “blank slate” when they were born, (2) nature and nurture each has contributions of its own, and (3) humans should not attempt to separate nature and nurture from one another because it is impossible. This belief was supported by a lecture from Wright State University (2002) which concluded that both nature and nurture contribute to one’s behavior. It even stated that nature can be used in explaining all the aspects of gender, dating and mating, and commonalities in personality between twins, and children and parents. On the contrary, nurture can clarify the details of prenatal and postnatal environment’s impact on one’s development, it can also elucidate the differences culture, and, lastly, it can also prove why children and their friends have many similarities.
Moore (2001) also claimed in his book entitled The Dependent Gene: The Fallacy of ‘Nature vs. Nurture that all human traits are caused by the interaction of genetic and environmental factors. He justified his belief by proving that hair color is not fully genetic because its color can be affected by environmental factors like diet. He explained that the amount of melanin – a substance which determines the hair color – is influenced by copper concentrations in hair-producing cells. He says that the darker the hair, the greater it consists of copper while the lighter the hair, the lesser it possess melanin. One can accumulate copper into his or her body through diet, copper is mostly found in mushrooms, chocolates, shellfish and nuts, and hence, if one is eating the said foods almost regularly, he or she might have darker hair.
In addition, according to Ridley (2003), human behavior is established on a “circular causation” by carefully probing on how human behavior is being determined by genes and how these genes are being affected by one’s behavior and environment. He also claimed that the debate between nature and nurture has been going on with many misconceptions and misunderstandings. Ever since, a lot of people already treated genes as a complete “blueprint” of who they are and that their actions have always been and always will be dictated by their genes. However, Ridley contradicted this by explaining that human genome – the whole genetic sequence and hereditary data of an individual – is a “recipe” mixed by genes and environment and the mixture of genes and environment and the genes’ interaction within itself and the interaction of the individual with his or her environment are the aspects which produce their behavior. Though genes controls heredity it does not control human behavior completely since they are capable in responding to the environment (Ridley, 2003). Genes are also what enables human mind to absorb his or her environment. Ridley also claimed that even though most things that a human should know are learned, it does not mean that human mind has been a “blank slate” at the beginning because intrinsic factors like genes are what enable people to learn that is why genes can do affect one’s behavior.
Moreover, while believing that nature and nurture do coexist, others then debated on which between the two of them affect the other greatly. There are others who say that “nature affects nurture” while others claimed that it is the other way around. According to Crosbie (2006), nature affects nurture directly or indirectly through reactive gene-environment, and passive and active influence, while nurture can affect nature because experience has a capacity to provoke systems that are innate. To support the latter’s argument, Crosbie cited Pascual-Leone (1995) who discovered that the part of brain which controls the movement of the fingers does increase in size over 5 days among those who play piano.
There have been many empirical studies about nature and nurture in order to prove which between the two really does contribute to one’s behavior. Among those studies were concerning twins and adoptive families. In both studies, people wanted to prove that it is nature that has a more influence in one’s personality development. On the twin studies, they have concluded that identical twins have more common attitudes, attributes and personality unlike fraternal twins even if they are separated at birth (Wright State University, 2002). This is probably because identical twins have more similar genetic make-up than fraternal twins, this is also proven true when identical twins are compared to non-twin siblings and they also concluded that fraternal twins have more similarities than non-twin siblings. In the case of the adoptive studies where the question is about if children that are adopted are more similar with their adoptive parents or biological parents (Wright State University, 2002). The findings of the study are that the personality of an adopted child is still more similar with their biological parents and that environment does not seem to affect his or her personality development. However, the adoptive parents could influence the adopted child in regards his or her views about politics, religion, and the like. This proves that genetics does not do the entire job alone (Moore, 2001).
Another study was done and was published on the December 1993 issue of American Journal of Psychiatry, this time, it is about personality disorders. The study was led by W. John Livesley, M.D., a psychiatrist in the University of British Columbia. He studied 175 pairs of twins to find out if hereditability is the reason of personality disorder development; they completed a set questionnaire that is used to assess the 18 dimensions of personality disorder (affective ability, anxiousness, callousness, cognitive distortion, compulsivity, conduct problem, identity problems, insecure attachment, intimacy problems, narcissism, oppositionality, rejection, restricted expression, self-harm, social avoidance, stimulus seeking, submissiveness and suspiciousness) called Dimensional Assessment of Personality Pathology (Livesly, Jang, Jackson, & Vernon, 1993). The findings were that broad heritability ranged from 0% (anxiousness, callousness, cognitive distortion, compulsivity, conduct problem, insecure attachment, rejection, restricted expression, stimulus seeking, submissiveness and suspiciousness) to 64% (narcissism). They concluded that even though several genetic factors affect personality disorders, some environmental factors have their own share, thus, making it appear that both nature and nurture affects one’s personality development.
However, a much recent study that was published in an online magazine, Science Daily, on April 23, 2008 stated that environmental factors like geography and lifestyle can affect whether genes will be turned on or off (North Carolina State University, 2008). Geneticists from NC State studied gene expressions of 46 Moroccan Amazighs and concluded that one-third of their genes are expressed in a different way due to their location and lifestyle. The researchers aimed to study the influence the changing lifestyles – traditional to urbanize – on human immune system by using modern tools to illustrate every sequence and expressions of all 23,000 human genes to compare the Moroccan Amazighs. They chose three groups of Moroccan Amazighs and they were chosen due to their common genetic make-ups but lived in a different environment. They found out that some genes and pathways that shaped by the environment and one of them is that respiratory genes in those living in urban areas are turned on unlike those in the nomadic environment, all in all, there were 30% of genes that are expressed differently (North Carolina State University, 2008).
Case Study: Erin Rivo
The case study focuses on a college student named Erin Rivo on May 4, 2008. She was adopted by a family who does not have any children when she was already 8 years old, her mother died of breast cancer while her father was convicted of murder when he killed a man that lived in the house that he and some other attempted to rob. In the course of the interview, I asked her if she can still remember some traits that she inherited from her parents and if her adoptive parents influence some of her present attitudes.
Q: Can you describe yourself?
A: Well, I’m a very shy girl at first that’s why I don’t have a lot of friends because they think I’m snobbish, people say that I look antisocial because my eyes’ gaze are too sharp and that they are always narrowed. But as time goes along and if I’m already comfortable with a certain person, I tend to show myself more as someone who has a good sense of humor. I’m also quite tactless at times; I tend to be very frank when I’m being asked for my opinion that’s why I accidentally offend some people unconsciously.
Q: The shyness, snobbishness, sense of humor, tactlessness and frankness, where did you acquire the traits that you mentioned?
A: I was not originally shy but I just feel…ashamed at the fact that my real father is a criminal that’s why even if other people don’t know, I feel that others may laugh at me or judge me through that. As for the snobbishness, I’m really not snobbish, though people thinks I am at first because I always narrow my eyes when I look around but that was because I have poor eyesight when it comes to far things so I narrow them so I could see clearly, even though I’m wearing contacts now, I still keep doing it. Then on my sense of humor, well I think I got that from the people who adopted me, every minute is a laughing minute with them. As for my tactlessness and frankness, my real mom is such an honest person to the extreme when she was still alive so I think I got that from her.
Q: You said you have poor eyesight, is it in your genes?
A: Yes, it is. It just got worse because when my real mom was already told that I need glasses already, I was just 5 years old then, we don’t have money so it was ignored.
Q: So it’s not because you watched too much TV or such?
A: No, I’m not a TV person but I think you could say that what made it worse is because I love reading books even with dim light. I was really thankful for my new parents because they gave attention to my eye problems.
This case demonstrates that nature and nurture are both equally influential in developing the personality of an individual. While genes predispose a person to think and behave in a particular manner, the people who actually interact frequently with him or her make an impact on her through experience. Over time, she may imbibe the characteristics of these people even if the latter are not her blood relatives.
I chose this topic because it also triggered my curiosity on which between nature and nurture has a greater effect on one’s personality development. I also want other people to know how a child develops his or her personality. Fathers always tells their daughters that they are just as smart as their mothers while mothers always tell their sons that they are just as handsome as their fathers, however, if the child caused some trouble, neither seems wants to say that she was their daughter or he was their son. Sometimes, there were also some people who will gossip about a neighbor’s kid on how smart he or she is and will that the kid’s parents are just average so they will assume that the kid is not the neighbor’s real child and he or she belongs to a much educated couple.
In those instances, I feel that the society is being unfair with the child because his or her own parents will also doubt if he or she was their child just because they never have engaged themselves in any trouble. At the same time, the parents will also blame themselves and would reminisce all the years of the child’s existence just so they could remember where they committed a certain mistake. Parents should be aware that they are not the only people the child interacted with, they should also think that their child also have friends outside their house and the child has a tendency to watch too much television enough for him or her to memorize every lines the actors and actresses give out. They should not limit on factors within their home or within themselves when it comes to understanding their child for there are other factors that affects a child’s growth.
Based on all the data and information that were gathered including the interview, it can be concluded that nature and nurture both affect a child’s development. There were just instances where one seems to contribute greater than the other. Whatever the child would be not only relies on his or her genes for the child will come across other factors in the outside world that could influence his attitude and character. Events, people, television, among others can affect one child’s way of thinking. Not all qualities are inherited from the parents, and same goes with talent. A child can sing or dance even though none of his or her parents does because those talents may have been acquired by the child with his friends, teachers or the celebrities the see on the television or hear in the radio. Even eloquence can not only be acquired through parents but through the books or other materials a child reads or listens to.
Crosbie, L. (2006). Perspectives: nature – nurture. Retrieved on May 5, 2008 from
Virtual Psychology website: http://www.virtualpsychology.co.uk/PERSPECTIVES
Livesly, W.J., Jang, K.L., Jackson, D.N., & Vernon, P.A. (1993). Genetic and environmental
contributions to dimensions of personality disorder. The American Journal of Psychiatry,
150 (12), 1826-1831
Moore, D. S. (2001). The dependent gene: the fallacy of ‘nature vs. nurture’. New York: Times
North Carolina State University (2008, April 23). Nurture over nature: certain genes are turned on or off by geography and lifestyle, study suggests. ScienceDaily. Retrieved on May 7, 2008 from Science Daily website: http://www.sciencedaily.com /releases/2008/04/080422150659.htm
Pinker, S. (2002, October 13). Sibling rivalry: why the nature/nurture debate won’t go away. The
Boston Globe, p. D1
Powell, K. (2006). Nature vs. nurture. Retrieved on May 5, 2008 from About.com website:
Ridley, M. (2003). Nature via nurture: genes, experience, and what makes us human. New York:
Rivo, E. Personal interview. May 4, 2008.
Nature vs. nurture. (2002). Retrieved on May 5, 2008 from Wright State University website:
Little Angel and Little Devil.
The above picture is of two babies, one wearing an angel costume while the other was wearing a devil’s. I believe that the moment a child is born, people look into the future to see if he or she will be perfect son or daughter or otherwise.