Nature vs. Nurture, Research Paper Example

Scientists approach the studies of behavior with two opposing concepts. There are those who believe that behavior is a result of nature or genetics and those who believe that behavior is a consequence of nurture or environmental experiences. Although there is a large quantity of scientific evidence that validate both theories, researchers have found that it is a combination of the two that truly determines an individual’s behavior. Researchers who work to determine the balance between nature and nurture in determining an individual’s behavior have conducted a wide array of studies which are psychological and biological and nature and range from the examination of DNA methylation to determine how genes that contribute to behavior are shut off to twin studies to determine how nature alters the personalities of two genetically identical individuals. As a consequence, nature and nurture determines a child’s behavior and some aspects of behavior are innate while others are learned.

As mentioned above, a series of behavior studies referred to as twin studies have contributed greatly to scientists’ understanding of how a child’s behavior is determined. These studies have involved the following of both identical twins raised by the same parents and identical twins who were adopted by different families. The goal of this type of study is to determine how people who have genetically identical backgrounds develop different modes of behavior based on different environmental factors. The scientists who conducted these studies hypothesized that twins that were raised in the same family would have more interests and similar features compared to twins who were separated at birth. A 1990 publication entitled “Sources of human psychological differences: the Minnesota Study of Twins Reared Apart” indicated that identical twins who were raised separately have an equal chance of being similar to their other twin based on aspects including personality, interests, and attitude compared to those who were raised in the same household as their twin. Other factors, such as IQ relies mostly on genetics (70%), but also depends on behaviors such as the parent’s involvement in the child’s studies, efficacy of teachers, and other environmental factors. Although this study makes a case for nature being the major contributor to the behavior of children, it demonstrates that nurture plays a role in conditioning certain genetic traits. The Minnesota Twin Study is being continued to identify other aspects of personality that differ among twins who were separated at birth versus those who were raised together. Overall, they found that “children who are orphaned, fostered, or adopted may have certain behavior or inheritable traits activated by certain environmental factors or adopted parents, but only within the limitations of their genes” (Land, 2011).

A second study of the relationship between nature, nurture, and behavior is the study of DNA methylation. DNA methylation is a naturally occurring process that our bodies use to silence our genes. For example, during development in females, one X chromosome is randomly silenced to ensure that the doses of genes allows for dosage compensation in the creation of proteins. Although the silencing of the entire X chromosome is a dramatic example, researchers have determined that DNA methylation occurs on the promoters of other genes as well. While some of this DNA silencing occurs during fetal development and is therefore somehow a part of “nature”, researchers have found that the patterns of DNA methylation on genes changes throughout the lives of humans and animals as a response to external stimuli. As a consequence, we are able to see how “nurture” physically exerts a gene silencing effect on “nature”. Unfortunately, this is a difficult process to elucidate and many researchers are puzzled as to how these changes actually come about. A recent article entitled “DNA methylation, the early-life social environment and behavioral disorders” indicates the belief that “modulation of DNA methylation in response to environmental cues early in life serves as a mechanism of life-long genome adaptation” and “under certain contexts, this adaptation can turn maladaptive resulting in behavioral disorders” (Szyf, 2011). As a consequence, understanding the connections between nature, nurture, and behavior will help scientists unearth clues regarding psychological disorders and determining better ways to find cures for these illnesses.

Although the Minnesota Twin Study and the study of DNA methylation are modern approaches to the understanding of the effect of nature and nurture on behavior, the relationship between nurture and behavior has been examined since the field of psychology has been developed. One of the hallmark experiments in understanding this relationship is Pavlov’s experiment that demonstrates the concept of classical conditioning. Ultimately, Pavlov proved that you can essentially encourage an aspect of behavior by repeatedly training an animal to respond a certain way. In his experiment, Pavlov would ring a bell before feeding a dog. He repeated this for a long period of time, and notice that the dog would salivate in the presence of the food. Pavlov found that when he would ring his bell in the absence of food, the dog would continue to salivate because it had learned that the bell is a signal for food (Pavlov, 1927). As a consequence, we learned that both animals and people have the ability to associate behaviors with cues and this is applicable in a number of situations. In a highly unethical experiment, John B. Watson attempted to prove that Pavlov’s concept would work on the conditioning of humans. To do so, he initiated an experiment that is now known as the “Little Albert Experiment”. Rather than using the food stimulus and saliva response that Pavlov used in his experimental design, Watson exposed a young child to a loud noise every time he was in the presence of a white rat. The loud noise would cause the child to cry, and the exposure was provided to the child over several week with the same response. Eventually, Watson ceased providing the loud noise, and the child would begin to cry each time he saw the white rat. In addition, since the white rat resembled other small animals and fur, little Albert showed fear towards these items as well. Although this sort of experiment would not be conducted today due to increased presence of ethical research concerns and regulations for the involvement of human subjects, Watson demonstrated that certain behaviors could be taught in response to stimuli (Watson, 1928). While many people don’t realize it, they don’t have to be involved in a study with experimental design to be subject to the effects of classical conditioning. Humans respond to stimuli on a regular basis. For example, because we hear about people getting hurt in car accidents on the news, we know to look both ways before crossing the street even when someone does not remind us to do this before crossing the street. As a consequence, these studies of classical conditioning are excellent ways to demonstrate the aspect of behavior that is determined by nurture or environmental impact. While the DNA methylation experiments and twin studies indicate that nurture is only able to impact us to the extent that our genetics allows, it is clear that this concept of classical conditioning is a universal mode of learning behaviors as a response of nurture.

In the modern world, we are extremely aware of the role that genetics has and can play in our daily lives; they determine how we look, act, and think. However, before the human genome project was completed or DNA was even discovered, early psychologists focused primarily on the relationship between nurture and behavior, because this element of nature was somewhat unknown and understood. As a consequence of this lack of information, many psychologists aimed to understand children behavior and development in terms of several developmental stages. One of these researchers, Erik Erikson concluded that there were several stages of psychosocial development that advance as a result of a concept known as “ego identity” which is defined as “the conscious sense of self that we develop through social interaction” (Cherry, n.d.). As a consequence, Erikson believed that all human behaviors developed by these interactions, which are considered to be nurture rather than nature. Erikson ascribed different ages and qualities to each psychosocial stage, indicating that all humans eventually develop according to these stages, although children may develop more quickly or more slowly than others based on the nature of their social interactions. The first stage of psychosocial development is called “Trust vs. Mistrust” and Erikson believed it to be the most essential stage of development. It occurs when the child is experiencing his or her first year of life and is based on the development of trust of others. Erikson believes that the child will succeed if he or she is able to develop trust because it will allow the child to feel safe and secure in the world and develop positive modes of thinking. Meanwhile, if the child is unable to develop this trust, they will become emotionally unavailable and carry out this way of negative thinking through most of their lives. While many people now believe that the psychosocial stages of development inaccurately describe the relationship of behavioral development due to the lack of inclusion of elements that would account for natural inheritance, this stage of psychosocial development closely reflects Pavlov’s classical conditioning. It would make sense that if someone commits an action to cause one to lose trust repeatedly, the individual will cease to trust others for the rest of his or her life. However, it is difficult to determine whether the issues of trust or mistrust could truly occur when a child is less than one year of age. The case of little Albert was a more realistic example of how classical conditioning could impact the behavior of children because it provided a readily available measure of the conditioning. Modern research also indicates that a child remembers very few of the life events that occurred to him or her before the age of three; therefore, if this type of classical conditioning were to impact the nurtured behavior of the child, it would likely need to occur after the time that the child started forming significantly memories. Only then will the repeated conditioning become effective.

Although the classical studies of behavior are essential to the understanding of the relationship between nurture, nature, and behavior as a whole, their primary usefulness is that these studies paved the way for more complex investigations of the causes of behavior that have determined many useful relationships between the two concepts that have allowed psychologists and physicians to direct their patient care practices. One article that utilizes the relationship between nature, nurture, and behavior to identify a clinically meaningful result is entitled “Maternal depression and children’s antisocial behavior: nature and nurture effects”. This is an example of a twin study that attempted to assess the relationship between genetics and a child’s tendency to become antisocial (Kim-Cohen et al., 2005). Young children were chosen for the study and this behavioral response was measured when the twins were at 5 and 7 years of age. The study found that “maternal depression occurring after, but not before, the twins’ birth was associated with child ASB and showed a significant dose-response relationship with child ASB at 7 years of age”. As a consequence, this relationship demonstrates that depression is connected to nurture to the extent of the genetics limiting these factors; if the mother had developed depression before the twins’ birth, there would have been more of a case for nature.

While a majority of scientific articles indicate that there is a balance between nature and nurture in determining the behavior of children, others believe that the specific balance between nature and nurture is dependent upon demographic factors, such as where the child lives. An article entitled “Nature vs nurture: outcome depends on where you live” attempts to explain this phenomenon. The author claims that “how strong environmental factors are in determining each characteristic, compared with the influence of DNA, differs significantly across the country” (Collins, 2012). A study at King’s College in London studied 45 childhood characteristics in more than 6,000 pairs of identical and non-identical twins and determined that certain areas can be considered “environmental hotspots” for certain traits. Although this study indicates the importance in understanding the relationship between nature and nurture, it indicates that the percentages of which factor contributes can vary depending on demographic factors. As a consequence, different aspects of nurture have a greater impact than others on the alteration of DNA and therefore behavior.

The differences in influence of nurture based on demographic differences again raises the question as to what causes these differences. Further twin studies have been conducted in an attempt to elucidate this relationship. A review article entitled “Nature versus Nurture: A Study of Adopted and Biological Children and their Behavioral Patterns” summarizes the studies that examine the relationship of adopted children with behavioral disorders (Grenke, 2012). Many people believe that children who are adopted are more likely to face behavioral disorders due to the personal challenges they typically face. Twin studies were used to study this relationship, and it was found that an adopted twin is more likely than twins that remain with their natural parents to develop behavioral problems. Although twin studies emphasize the genetic and behavioral similarities between twins, this study indicates that certain experiences involved in the adoption process are traumatic and significant enough environmental factors to contribute to the differential behavior of the adopted twin.

Since the aforementioned studies have indicated that there is a balance between nature and nurture in defining the behavior of children, researchers believe that it is also possible to take advantage of this balance in order to teach parents how to raise their children in a way that maximally encourages positive behaviors. The article “Parenting and its Effects on Children: On Reading and Misreading Behavior Genetics” provides a collection of experimental evidence about the relationship between nature, nurture, and behavior, and suggests that although we cannot control the nature aspect of children’s behavior, we can take advantage of the nurture aspect by enacting good parenting skills that will allow the children to develop desirable behaviors (Maccoby, 2000). She reports that parenting typically accounts for 20%-50% of variance in behavioral outcomes, showing that in some cases, good parenting can overcome the boundaries of genetics that code for bad behavior. One of Maccoby’s most significant suggestions is that parents who have children that demonstrate bad behaviors should alter their child rearing practices. When children were assigned to experimental interventions to control their behavior by random selection of family, their behaviors improved significantly and these effects were found to be independent of genetics. Maccoby also describes the phenomenon of siblings who exhibit different behaviors. In cases with siblings who were born several years apart, it is important to consider that all of the siblings are not genetically identical nor do they typically receive the same type of nurture due to different parenting of each child. The first child is usually well-behaved because new parents typically invest a majority of their resources into the well-being of their new child. These parents are typically stricter about what the child is allowed to do, and they ensure that the child has supervision at all times. A second child is usually allowed more freedoms than the first child because the parents have already gone through the major stressors of parenting with the first child and believe that they have more skill. As a consequence, the child is supervised less and allowed more freedoms which enhance the likelihood of the child to develop behavioral problems. If the second child is the middle child, he or she may also feel like her or she is being ignored and act out on purpose in order to receive attention. Subsequent children may also follow the behavior of the second child depending on the attitude of the parents. It is therefore clear that birth order has somewhat of an effect on the behavioral development of the child, however since the differential treatment among children is the main cause for these differences in personality, it is entirely possible for altered child rearing methods to be used to enhance the likelihood of all children behaving regardless of birth order and distance in time between the births. Since the first child is generally more responsible and least likely to act up, parents who have had these results with their first child should make every attempt to continue this pattern with their future children. It is essential to make time for every child in the family regardless of birth order and to ascribe to them equal responsibilities. If the children are treated equally, they will begin to develop equal behaviors.

It is especially important for parents to interpret and understand the parenting techniques they are using to raise all of their children. Maccoby mentioned that interventions involving changing the parental style aided greatly in psychological studies. Therefore, parents should be taught to recognize what techniques they are using and be able to change them when they determine what they’re doing isn’t working. One of the main factors in conditioning a child’s behavior depends on the concepts of punishment and positive reinforcement. In a lot of cases, children who are punished regularly for their bad behaviors will not stop the behavior. Instead, they will feel negative emotions towards their parents for the punishment because they believe it is not deserved, which will cause them to repeat the behavior and/or adopt other behaviors that are considered negative. When parents who are punishing their children realize that this is not solving any problems, they should switch to methods of positive reinforcement instead so that negative behaviors will be ignored but positive ones will be rewarded. This is the best way to maximally ensure that nurture is being taken advantage of in parenting.

In conclusion, both nature and nurture play a major role in determining the behavior of children. In a sense, DNA modification and environmental stimuli have a “chicken and the egg” effect in which DNA modifications could cause environmental stimuli and environmental stimuli can cause DNA modifications. Despite the uncertainty of how one impacts the other in fine detail, we are aware that there is a balance between the two in determining behavior and that different demographics will impact the proportion of importance that each characteristic has. Scientific studies will continuously be conducted on this subject and we may one day finally understand how both nature and nurture combine to impact child behavior.

References

Bouchard TJ Jr, Lykken DT, McGue M, Segal NL, Tellegen A. (1990). Sources of human psychological differences: the Minnesota Study of Twins Reared Apart. Science. 250(4978): 223–228.

Cherry K. (n.d.). Erikson’s Theory of Psychosocial Development. Retrieved from http://psychology.about.com/od/psychosocialtheories/a/psychosocial.htm

Collins N. (2012). Nature vs nurture: outcome depends on where you live. Retrieved from http://www.telegraph.co.uk/science/science-news/9326819/Nature-vs-nurture-outcome-depends-on-where-you-live.html

Grenke CJ. (2012). Nature versus Nurture: A Study of Adopted and Biological Children and their Behavioral Patterns. Retrieved from http://digitalcommons.liberty.edu/cgi/viewcontent.cgi?article=1307&context=honors

Kim-Cohen J, Moffitt TE, Taylor A, Pawlby SJ, Caspi A. (2005). Maternal depression and children’s antisocial behavior: nature and nurture effects. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/15699294

Land J, Land M. (2011). Adoption Detective: Memoir of an Adopted Child. Wheatmark.

Maccoby EE. (2000). Parenting and its effects on children: On reading and misreading genetic behaviors. Retrieved from http://www.annualreviews.org/doi/pdf/10.1146/annurev.psych.51.1.1

Pavlov, I. (1927). Conditioned Reflexes. London: Oxford University Press.

Szyf M. (2011). DNA methylation, the early-life social environment and behavioral disorders. J Neurodev Disord. 3(3): 238–249.

Watson, JB. (1928). Psychological Care of Infant and Child. New York: W. W. Norton Company, Inc.