Thursday, October 22, 2009

Analysis of Nature vs. Nurture (UPDATED)

We all have strong opinions on how we became and who we really are. It is obvious that physical traits are mostly inherited. I did not get my brown eyes from spending too much time with my best friend, nor will my eyes change to a blue color if I spend too much time with another friend. I will not suddenly grow taller if live next to and see a tall man every day. Anyway, I think you get the point. The environment and our surroundings will not change physical traits like eye color or height, only surgery can do that…

Indeed, there are two sides to this argument: behavior is determined by our genes and behavior is shaped by our environment. While in the past few posts I argue for the environment, or nurture, shaping our personalities, there is also evidence for the nature theory as well. I understand that both sides are valid arguments; however, I see that nurture plays more of an important role in shaping behavior. I will examine arguments for both sides by examining certain issues in this post. Each paragraph below will focus on one idea.

Where exactly did this all begin? Well, the nature versus nurture debate can be traced back to 13th century France. A man named Francis Galton used "nature" and "nurture” to discuss the influence of genes and upbringing on development. Galton states that “nature is all that a man brings with himself into the world; nurture is every influence that affects him after his birth.” What Galton stated at this time is very similar to the definitions of nature and nurture today. On the whole, the nature vs. nurture debate has its roots in France.

Personality Development
In order to understand the nature vs. nurture debate, an understanding of personality development is necessary. Psychology has many theories about personality development, but first let’s examine exactly what personality development is. Personality development is the pattern of behaviors and attitudes that is unique to a person. Personality development is a result of the interaction between temperament, character and environment. Temperament is the genes that determine an individual’s view of the world. There are no genes that specify personality traits, but some genes do control the development of the nervous system, which in turn controls behavior. Looking at this, genes seem to have an indirect role in personality development. Now, I will explore different topics as they relate to nature and nurture.

Let’s look at a common topic like intelligence, for example. Asian-Americans, Jews and West Indian Blacks have been unusually successful. An intelligent father and mother will not necessarily give birth to an intelligent child, and an intelligent child can result from not-so-bright parents. Intelligence is quite malleable and owes little or nothing to genetics. Effort plays a major role in intellectual success. Because of culture and parenting, these groups work harder and do more with what they have.
There is also a correlation between the verbal ability scores of biological parents and their children compared to adopted children and adoptive parents.
Personally, I can relate to this issue. Both of my parents immigrated to the United States from Vietnam. Thus, they knew little English and had difficulties communicating. This communication barrier blocked their path towards receiving a high education. As of now, my parents are intelligent enough to get through life. In addition, they received mediocre grades; they were not the brightest. However, my parents say that both my brother and I are “more intelligent” than them. Were my brother and I influenced by our environment? Did our parents teach us how to become more studious? On a lighter note, some of my mom’s coworkers have joked saying that where did my brother and I get our intelligence.

What about obesity?. The connection between genetics and intelligence is not as clear as between genetics and obesity. In most cases, genetics determines our size and weight. Now that does not mean that those who are overweight have little hope in changing their lives. With determination and will, one can slightly overcome the genetics and lose weight. Although you may not be the model type, you will be in a healthier weight range. Diet and level of physical activity are important. There are some people who are obese, and yet they have tried everything. 77% of obesity is genetic. Obese children can be doing the exact same activities as the less obese children. It is wrong to stigmatize them and blame parents without knowing about their actual eating habits and lifestyle. (Just a little side note: I have always wondered what the results would be if I ate as much as I wanted, whenever I wanted. It is easy to gain weight but difficult to lose, in most situations). The obesity example shows that genetics plays a major role, but the environment can re-shape those influences.

Usually people stereotype and say that Asians cannot be obese because it is in their genes. I agree with this to a certain extent. No one in my family is obese; however, two of my cousins have gotten a little chubbier. I believe this is due to the food they have eaten. Genetics can only “protect” you from so much. On the other hand, my dad consumes quite a large amount of food, yet he remains around the same weight range. On rare occasions, some people have trouble gaining weight and say that they cannot do it. Gaining weight is A LOT easier than losing weight for sure. They just have to try to eat more…it is as simple as that.

Criminal Behavior
As with the connection between genes and obesity, the connection between genetics and criminal behavior is also debatable. Scientists say that some people are more inclined to commit criminal acts than others. A study performed by Tehrani and Mednick in 2000 revealed that compared to the control group, “the adopted individuals, which were born to incarcerated female offenders, had a higher rate of criminal convictions as adults.” The diathesis stress model states that there are individuals born with a predisposition for violence but may or may not be violent depending on environmental factors. There is also evidence of brain abnormalities contributing to aggression, and serotonin levels are linked to aggression. These two aspects are linked with genes.

There is a misconception that both genes and environment play a role in the criminal status of the individual, and it is not always true. First, what exactly is the environment? Parents share your genes, so being raised in a violent family cannot be technically considered "environment." It is like genes reacting to genes. What would this be considered as?

Contrary to the previous topic, divorce and genetics have a connection. A twin study suggests that genetics has a strong influence on length of marriage. Marriage and divorce rates were compared in identical and non-identical male twins. Results show that identical twins are more likely to follow the same divorce patterns than non-identical twins, which indeed suggests a genetic influence on divorce.

Wild Child
Consequently, environment can be definitely considered in the wild. The question at hand is whether behaviors are influenced when a child grows up in the wild. Indeed, living in the wild is completely different than living in a nice, comfy home. In the wild, animals hunt for food and live on their own. Here is a case of a child living in the wild:
A Cambodian girl went missing when she was 8 years old. When found 18 years later, she was hunting for food, walking on all fours and not speaking any intelligible language. This is one of the many cases involving children raised by animals, similar to Romulus and Remus who were raised by wolves. What can we learn from the discovery of the existence of wild children? They would not be able to communicate or show empathy with other human beings and would be unaware of the needs of others. Concepts such as morals, property and possessions would be mysterious to them. If brought up by animals, they would not identify themselves as human. This phenomenon may lead to conclude that upbringing is “entirely responsible for providing humans with language, the ability to think and the concept of our own humanity.” What happens in childhood has a deep impact on neurological development. However, the brain does control neurological functioning and genes influence intellectual ability (influence, not form…considering the intelligence paragraph above).

Childhood experiences in relation with behavioral traits are a topic that Sigmund Freud examined. Freud said that personality develops by age 5. Childhood is the most important part of personality development. We are born with our id, develop our ego through interaction with the environment and form our superego, or conscience, by age five. Looking at Freud’s theory of personality development, behavior is shaped mostly by the interactions that the child has with the world before age 5. Freud does not mention anything about genetics. While this holds some truth value, events past childhood have the potential in changing one’s personality as well, although childhood events may form the foundation for the future.

In A Larger View
Genetically inherited traits have an impact on how others see you and how you see yourself. If you have poor motor skills and cannot throw a ball straight, then your peers may label you as an incompetent baseball player. Because of your label, you perceive yourself to be a failure. Skin color, gender and sexual orientation are also likely to influence how you perceive yourself as well. Whether you are accepted or unaccepted by others can engender you to behave in a socially acceptable or deviant way.

Causal Relationships

Everything is related, right? Well, it depends on how you look at it. Nature and nurture exert influences on one another, but they are not necessarily a “cause-effect” relationship. The interactions among hormones, brains and behaviors are intricate.

An example of culture’s influence on biology is that adolescents are going through puberty much younger than before. Perhaps this is the result of exposure to “grown-up” influences in the teenage years, or because of higher stress.

However, as said before, the link between a gene and a behavior is not the same as cause and effect. While a gene may increase the likelihood that you'll behave in a particular way, it does not make people perform in certain ways. There is still room for choice and free will.

The Other Sides
There are those who argue for nature, and there are those who argue for nurture. In addition, there exists euthenists, who believe bad parenting and society’s evils cause all problems, and the supporters of eugenics, who blame faulty genes for all of society's problems and want to prevent all "bad" people from reproducing. These two other sides do not attribute a cause to behavior but attribute a cause to BAD behavior.

A Scale
Imagine a scale with nature on one side and nurture on another. Which side is heavier? Where do you belong? This concept of the scale or spectrum is also seen in politics, with conservative on the right and liberal on the left. Conservatives lean towards nature and liberals towards nurture. Like this spectrum, there are people in the middle, moderates. There are people who argue in favor of nature while others for nurture, but there are exists the ones in the middle, arguing for both. So, now you might wonder why there was even a debate in the first place.

There is a debate between nature and nurture because of uncertainty. People are not sure, and this creates tension to find out the right answer. If you were given two choices and only two choices (nature or nurture, for example), then you would answer “both,” but “both” is not one of the choices.

In A Nutshell
Yes, nature and nurture both play a role in personality development, but what scientists are trying to figure out now is exactly how much each part contributes to behavior.


  1. this was an awsome help. thanks bro, helped alot for my research

  2. who is the author?

  3. Great post - insightful and so very thought provoking. A subject which is a constant curiosity to me. I come from an extremely large & close family, look forward to being a mother, accept everyone for who they are but do wonder at times, where traits, life choices and mannerisms have come from in family and friends who are adopted or chosen a different path in life despite a similar upbringing.
    I find it incredible - thank you :)

  4. Please can an author be named. Would love to cite some of these blogs. :) I am writing a paper on Nature vs. Nurture in Criminology. Great stuff here. Thank you :D

  5. Really thank u it helped me alot in my personality development assignment