Through the completion and in-depth analysis of a number of case studies on twins, it was shown that nature does indeed play an important part on one’s intelligence. The presences of certain traits that enhance intellectual ability are passed on in the form of genes. As new research comes out, it is being shown that genes can be altered, which means that although the presence of these desirable traits are found in genes, it is not always guaranteed that they will be passed on. Another way to look at the same point is that genes can alter so that the traits slowly evolve from less desirable ones to more wanted ones.
Nurture (environment), also plays a key role as a determining factor on one's intelligence. This is because of the following; Life experiences alter the influence of different factors on one's intelligence. Factors such as the availability of education and upbringing are key players that have an impact on the all round development of a persons intelligence. Much like a persons environment, intelligence is ever changing though time. Education and proper upbringing is needed throughout a person’s life starting from birth to adulthood. During childhood, people learn their foundations of knowledge (beliefs, customs and activities that encompass a child’s habitat). From the educational standpoint, children learn their fundamentals (reading, writing, interaction). Since environment can override some genetic foundations it can be said that intellect does not rely just on genetics as its sole factor. For example, a student that has a talent in mathematics (genetics) is likely to take more math courses in further education (environment). So in this way, the talents in mathematics (nature) along with the experience of doing well in the subject (nurture) work cooperatively. Genetics (nature) gives us the ground basics to comprehend what the environment (nurture) attempts to teach us.
In the same way that nature played an important role in determining ones intelligence, nurture has an equal importance. Nature (or genetic makeup) begins the foundation of ones intelligence. This means that some people have a “head-start” by having more desirable traits in their genes. This however does not remain constant throughout life. Through different life experiences as well as education, people gain and lose information in different ways due to their environment (surroundings). This aspect, referred to as nurture, plays a just as important role as nature in determining one’s intelligence that develops throughout life.
Personality is the complex of characteristics that distinguishes an individual's behavioral and emotional characteristics. Behavior is the response of an individual, group, or species to its environment, or anything that an organism does involving action and response to stimulation. (Webster) When discussing how heredity influences personality and behavior, the nature position attributes different characteristics to genes. In heredity the way genes are used is also referred to as instincts and inherited traits. () It is recognized that certain genes do have an influence on personality and behavior.
There are three main ways in which personality and behavior are affected by heredity. Firstly, human traits give certain abilities. An example of this is language. Humans converse and produce vocal sounds with the aid of the vocal cords, jaw, teeth, tongue, etc. Fingers are other examples of these traits. Fingers help handle and manipulate different tools. Without certain physiologies, the way human’s work and think would not be as significant as it has evolved to be today. It is through the use of these so-called traits that behaviors begin to emerge. Basically, what you use your hands to do, and how you use your hands affects your behavior.
Other physical traits affect the psychological aspects of a person. An example of this is a person’s gender and a person’s age. Any society around the world organizes the roles and different identities to people based on a number of different things, which include sex and age. One’s genes designate a person’s gender. This means that the natural aspect determines gender. Analyzing the American society, different roles begin to emerge. The sex of a person contributes greatly to how one’s personality and behavior develops. An example of this would be a teacher. An analysis showed that the majority of the teachers in the United States are female. When examined even more thoroughly, it is found that females tend to be more sensitive and more caring in relation to other people. How the female teacher behaves with her students is instilled as part of her personality. This personality further leads to how she behaves with other people. A sensitive side shows a more caring and understanding type of behavior. It is due to the effects of the sex (that is that females tend to be more caring) that affects how he or she interacts with others on a general scale. Behavior and personality, in this case, go hand-in-hand. It is through behavior that one begins to develop unique personalities. So, nature (genes) actually directly affects personality and indirectly affects a person's behavior. Nature affects behavior indirectly in the sense that genes determine ones personality up to a certain extent. It is through this instilled personality that one behaves in different ways.
The third way heredity (nature) influences personality and behavior is through our inherited composition. One technique to determine if this theory is true is through case studies relating to twins (identical and fraternal). As discussed before, twins are an important factor of study for this controversy. The comparison of identical twins (monozygotic twins) and fraternal twins (dizygotic twins). IQ, as discussed before, is very similar in the two types of twins because of their genes. In the same way, identical twins share very similar personalities and behaviors because of their identical genes. A single fertilized egg that split into clones produces identical twins. (Dunn, Judy, Sisters and bothers, p146) An example of identical twins that display inherited behavioral patterns is Jerry Levey and Mark Newman. The two men met in a bar, and had grown up in different environments. It was soon found that they demonstrated behavioral similarities such as drinking the same beer, holding a bottle the same way (held it with the little finger stretched beneath the bottom), having the same physical gestures, being involved in the same careers. (Reunited Twins) The twins displayed these characteristics even though they grew up in different environments. This shows that it is true that heredity does play a role in determining personality. Fraternal twins do not share the same quality because in the early stages of growth in the mother’s womb, the eggs are split and two new zygotes are formed. Through this study, it was found that heredity does play a role in determining personality. Another relationship that was discussed before was that between adopted children and their biological parents. This is an ongoing study, and so the results are not yet known. If there is a match in the personality between the biological parents and their children in foster homes, then the nature perspective gains advantage. If there is a match between adopted children and their foster parents, however, this is due to their environment and therefore the nurture perspective gains an advantage.
A more scientific approach to how nature affects personality and behavior was also researched. “Hereditary instructions carried by the chromosomes influence development throughout life by affecting the sequence of growth, the timing of puberty, and the course of aging.” (Introduction to Psychology, Pg. 379) The timing of these developments all affect how our personality develops. Based on another case study on twins, Michael Bailey of Northwestern University revealed an important finding on identical twins. He found that if one twin is homosexual, “there is a 50% likelihood that the other will be too.” (The Personality Genes Pg. 60) Male homosexuality was linked to a strand of DNA near the end of the X Chromosome. This finding in a way proved that genes affect sexual orientation, which plays a key role on how people behave and interact with others. It also plays an important role on how personality develops. Another finding from the same experiment was that chromosome 17 played a role in regulating the feeling of anxiety. (The Personality Genes) Anxiety is an important part of how a person behaves and how ones character, or personality, develops. Anxiety and sexual orientation are both, in their own way, an important part of how people interact. The greater the anxiety, the more impatient one is, and therefore the more irritated he or she would be. This would show not only in their personality, but their behavior as well.
From the same experiment at Northwestern University discussed earlier, it was also found that genes increase the production of the production of proteins. These are proteins that are found in organs like the kidney and the brain. For example dopamine is a chemical that creates sensations of pleasure in response to intense experiences. It affects brain processes that control movements and emotional responses. People that inherit the gene that is responsible for the dopamine “might seek to stimulate its production by seeking out thrills”. (The Personality Genes Pg. 61) Therefore, these people tend to seek adventurous and thrill-seeking personalities. Heredity, as it was shown, engages in the type of personality that a person may develop. People with thrill seeking and adventurous personalities will also behave in such a way that their personality will match their behavior.
Another fact that shows that Nature greatly influences personality development can be seen in infants. “Genetic variations that influence dopamine and Serotonin receptors in the brain may cause some babies (and adults) to be bolder or more curious than others.” (Reuters, Pg. 1) Some babies, for example will attempt to climb things such as stairs or even descend them, while others will be more cautious and therefore will not attempt anything risky. Other similar examples are a form of a dopamine receptor gene that was found in 2-week-old infants with a wandering behavior. The gene affected how the baby behaved. If the gene was present, the baby was found to wander around and not remain attached to one area. However the lack of the gene resulted in some babies that wandered slightly, and others that barely wandered at all. (Reuters Pg. 1)
Other studies have shown that other parts of personality are linked to genes as well. Personalities related to alcoholism, depression, obesity, and different phobias are all linked to genes and therefore the nature aspect. (How Genes Shape Personality, Pg. 59) Traits such as aggression, criminal tendencies, and intellectual ability are all intermingled within different genes. This study by Sarnoff Mednick from the University of Southern California shows that certain personality traits are inexorable and so are bound to happen. (How Genes Shape Personality, Pg. 59)
Through many different aspects, it was shown that nature plays a big part in determining ones personality and behavior. Not only does it play a part in determining the personality and behavior, but it also affects how, throughout the course of life, personality and behavior change. Through many different case studies on different people (twins, adults, etc.) as well as through scientific research in genetics and other areas, it was shown how big a part nature plays in the affect of genes on personality and behavior. Heredity (nature) affects how personality and behavior change both directly and indirectly. In some cases, personality is the medium through which genes affect behavior, while in other situations it is behavior that is the medium through which genes affect personality. All in all, nature does in fact have great importance as the determining factor of personality and behavior.
In the same way that the nature viewpoint plays a role on the development of different personalities and behaviors, nurture produces an equal effect. Nurture, again, is the environment in which a person lives or has lived in and how that environment affects his or her upbringing. Intelligence ties in directly with behavior. Dr. Glen Doman of the Philadelphia Institute for the Achievement of Human Potential has shown through many case studies that the environment influences ones intelligence, and therefore one’s behavior and personality. His case study was based on the concept that if a child is nurtured and taught by his parents at the very critical and decisive years in life (i.e. early childhood), then a child’s IQ will change in a positive way, and therefore, the child’s behavior will also change. By teaching children at the right stage in life, he showed that even disabled children were able to improve their IQ and change their behavior. Basically, if a child was brought up with good moral support, and was instilled with good traits, then intelligence of that child was at his or her prime. Intelligence would lead, then, to a better understanding of various things and how they work. Formulating a more rich and productive personality via intelligence, would change how the child would interact with the world around him or her (behavior).
Another aspect of nurtures affect on behavior and personality deals with society. Recent technology in different societies has altered many natural aspects. For example, it is not uncommon now for a person to artificially enhance certain parts of their bodies with surgery, or chemicals (such as steroids). This new technology is an example of nurture. The environment can also, in this case, be referred to as the society. The society, then, portrays an image of beauty that people try to match. By doing so, people’s confidence rises, and therefore they are able to interact better with others. This alteration of or in their body changes the way they not only see themselves, but also see the world around them. This perspective also leads to a change in personality. A new confidence, as stated earlier, leads to a different outlook. With a changed outlook on life, and modified interaction methods, personality, and in due time behavior, change. This shows another way in which the environment, or nurture, has an affect on a person’s personality and behavior.
Although not as great as nature in this case, the study of the environmental upbringing’s (nurture) affect on personality and behavior is an ongoing one and so many case studies are inconclusive. What is known, however, shows that nurture affects how people respond and interact with the world. The setting of people, in this case, is a very important determining factor. How and where a person is raised plays a key role in how that person’s personality and behavior develops. This means that society, whether it be of any nation, will indeed affect how people not only interact and view the world (personality), but also how people will act in response to that very society as well as to the rest of the world (behavior).
After extensive research on a variety of case studies and results from various other scientific research experiments, it was found that nature and nurture both have a great affect on a person’s intelligence, personality, and behavior. Nature (heredity and genes) plays a greater determining factor for personality and behavior than nurture (surroundings) does, while nurture plays a slightly greater role in determining one’s developing intellectual ability. Life encompassing an individual is made up of an infinite amount of activities, functions, and responsibilities. Nature fulfills some of these many life processes as does nurture. There are many cases where nature starts out by playing a greater importance, and then the supremacy shifts to nurture as life progresses. It is important to realize that the debate over nature versus nurture is an ongoing one, and one that is likely to continue indefinitely. Most of the research that has been conducted encompasses the basics of this debate. The results of this research show no inclination to either side of the argument, and so it can be concluded that both nature (genetics) and nurture (surroundings of upbringing) play an equal role in the affect on all types of life processes in humans.
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