Discussion about what factors –genetic or environmental - play the more significant role in humans’ development had begun a long time ago. Scientists conducted many studies to find the answer to the question of what is more important for the development of intelligence, personal traits, lifestyle habits, etc. Some authors adhered to extreme points of view that the only environment shapes a personality (for example, Skinner, founder of behavioristic approach) and other authors considered an influence of nature as foreground force in comparison to nurture (Linden, 2012, p. 54).
On the one hand, scientists concluded that influences of genetic and environment intersect and complement each other. That`s why it is impossible to state that a particular personal trait, habit, etc. was caused by a single influence of environment or hereditary. On the other hand, different studies demonstrated that sometimes nurture can be more influential than nature and vice versa.
In this essay, we will try to discover evidence of those cases when environment, upbringing or the lack of nurture influence development of human personality more than nature. Geertz indicated that culture was essential to condition and not only additional factor of human existence.
Questions about an influence of nurture refer to questions about the effect of socialization, culture in humans. If we want to understand how strongly socialization influence human development we can imagine how people will look alike without any environmental influences. Such real life examples as cases of Genie (“Wild Child”) and of Victor ( a boy who grew up among animals) are the demonstration of what happens to children who isolated from society and environmental influences.
Genie was isolated from society and deprived of affectionate interactions by the own father who kept her locked in the room. She spent in her room approximately ten years. When police found her she was at the age of 13 years, however, her level of development was similar to a developmental level of a three-year old child. Genie had not the ability to speak, to control her urination, etc. Educators, psychologists, and other specialists tried to teach Genie to speak, and they even achieved some result, but Genie has never mastered and understood the grammar of the language, etc. Her case, on the one hand, indicated that there are some biologically determined critical periods in the development of children. On the contrary, the example of Genie demonstrated that biological factors, genetics are not enough for shaping a human personality (Gould& Howson, 2011).
Craig talking about the role of biological factors and environmental factors in adolescence indicates that adolescents experience rapid and intensive hormonal changes, and many parents believe that these changes are the reason for teens` depression, risky behavior, aggressiveness, etc. However, Craig emphasizes that according to results of different studies there is no stable association between adolescents` negative behavior and hormonal changes.
At the same time, results of various researches show that adolescents raised in dysfunctional families tend to demonstrate delinquent behavior more often than adolescent raised in families with “healthy” relationships. It means that behavioral problems of adolescents are more likely to be determined by family environmental factors than by biological factors such as drastic hormonal changes (Craig& Baucum, 2002, p. 636)
The brain of a 5-year-old child in size is almost the same as that of an adult. Brain structures in early childhood are plastic and flexible. A child after one`s birth has approximately 2,500 synapses. For 2-3-year, the number of synapses in neurons increases to 15000 (Craig& Baucum, 2002, p. 319). But what is the reason for the growth of synapses amount from birth till adulthood? Is it a genetically determined process which takes place independently of environmental influences?
As showed cases of Genie and other feral children mentioned above, the brain structures cannot adequately develop without external stimuli, without social interactions, communications, and emotional connections.
One famous experiment conducted by Mr. and Mrs. Kellogg showed impressive results which also explain the role of nurture and nature in human development. Kellogg spouses suggested that if they raise infant of chimpanzee like a child together with their 9-months-old son Donald, the animal will imitate humans’ behavior (Schusterman, 2010, p. 100).
Kellogg had expectations that chimpanzee would be able even to master human speech. However, in a result of this experiment Kellogg`s son had suffered. Instead of being the example of behavior for the chimpanzee, Donald himself began to imitate the behavior of the monkey, to degrade and demonstrate the delay in language development. On the one hand, this experiment showed that animals (and, maybe, humans too) cannot go beyond their nature. On the contrary, the research demonstrated that the lack of proper nurture, environment, etc. can determine a retardation and delay of development of a child even if this child has all genetic predispositions for healthy development initially (Schusterman, 2010, p. 109).
One of the best methods to indicate what traits, features of personality are determined by nature and what one are determined by nurture is a study of identical (reared apart or together) and fraternal twins. Most of these studies prove that influence of hereditary plays more significant role in the determination of personality traits than nurture does. However, few studies also indicate that nurture plays major significance over nature.
For example, researchers examined the sense of humor of 127 pairs of fraternal and identical twins. Results were unexpected and indicated that correlation between scores of a sense of humor was higher in pairs of dizygotic twins. Such results showed that shared environment influence development of a sense of humor more than genetic factors (Cherkas, Hochberg, MacGregor, Snieder & Spector, 200, p. 21).
Another twin study showed that environmental factors also have an influence on the IQ. This study demonstrated that if one of the identical twins was raised in a family with low income and another twin was raised in a family in a middle-class household, the differences in IQ scores between this twins was noticeable. However, if one of two twins was reared in a wealthy family and another twin was reared in a middle-class household, there was no significant difference between two identical twins in general intelligence scores (Linden, 2012, p. 54).
Saudino pointed out that genes only suggest some range of possibilities, but do not provide realization of these abilities. However, people cannot change their genes, but they can choose their lifestyle, habits, etc. Genes determine 30-50% of an individual`s personal traits, but the rest of feature of a personality depends on the environment, as scientists state.
Saudino indicates that parents cannot know or decide what talents and predispositions their children will have at birth. Also, parents cannot force a child to be talented in that field of science, art, a profession they (parents) would like a child to be. At the same time, parents can influence a child development significantly if they will react positively to a child`s interests, activities, etc. Saudiono believes that the best environmental impact for the development of a child is parents who support their kid, understand his/her interests, see his/her talents and allow their child to maximum reach his/her potential (Glass, 1999).
So after the analysis of results of different studies experiments it can be concluded that there more evidence about the dominant influence of hereditary on human personality than proof of that education, an environment can overcome human genetic predisposition. However, culture, nurture, social, environmental influences determine that a child growth into a human adult and not into an animal. Besides that nurture create a particular framework for the development of those abilities which is determined by nature.
References
Cherkas, L., Hochberg, F., MacGregor, A. J., Snieder, H., & Spector, T. D. (2000). Happy families: A twin study of humour. Twin Research, 3(01), 17-22.
Craig, G. J., & Baucum, D. (2002). Human development. Upper Saddle River, N.J: Prentice Hall.
Glass, J. (1999). Nature Vs. Nurture. Parenting, 13(10), 156-160
Gould, M., & Howson, A. (2011). Social Isolation & Human Development. The Process of Socialization, 160-167.
Linden, D. J. (2012). The accidental mind. Harvard University Press.
Schusterman, R.J. (2010). Historical Perspectives. Aquatic Mammals, 36(1), 84-110.
