Nature vs. Nurture Genes or Environment

 Throughout the course of psychology, one debate constantly plagues the minds of psychologists alike. Whether personality and behavior is more based on genetics or how we are raised, commonly referred to as nature versus nurture. Nature, anything inherited or biological, and nurture, anything affected by our environment and experiences. In the past, psychologists traditionally took an extremist point of view. Those who take a nature perspective are nativists, while those who side with nurture are empiricists. With modern psychology, it is more common for psychologists to take both into account. As research has proven how both of them influence personality and behavior. Given this, there is lots of information on the two subjects. Though when focusing on nature, light can be shed on why it would be more influential.

For nature, the first set of evidence you can look at is the brain and body. There are many hormones and areas of the brain that majorly affect the way we act. Starting with the brain, there is the frontal lobe. One of its primary functions is helping with emotional expression. Once, a man by the name of Phineas Gage had his frontal lobe damaged. A rod was shot straight into his head and went through his frontal lobe, despite the severity, he survived. After that, he went from a once friendly, nice person, to being easily angered or irritable. Located in the lower brain, we have two sections called the hippocampus and amygdala. These work together to help regulate our emotions. If one is damaged, it becomes hard for a person to maintain that ability. The central nervous system contains what is called the cerebral cortex, which is in charge of all four lobes. Two of these lobes are the parietal and temporal lobe, they also play a role in emotions and behavior. 

Damage to there could play a part in affecting that, for example. If the parietal lobe were damages, someone who is calm and easygoing might become very easily angered or irritable About the same thing goes for the temporal lobe if that is damaged. Hormones are also a big part of how we are acting, as they control your behaviors and emotions. Any type of imbalance of these may, for example, make you a lot more sensitive than usual. Another big role in our personality are all the neurotransmitters. A popular example of this is serotonin, which is well known to cause depression if there is an imbalance. There is also the pituitary gland, which majorly helps with regulating mood and behavior. This one gland can be the start to a number of mental and/or emotional issues. The many different parts of our bodies that have effects on our mood and behaviors, is only a small part of how nature really affects us.

Not only does the brain affect your personality, but DNA also plays a large role in it. One large factor that goes into it are genes, which one inherits from both of their biological parents. Lots of different studies have shown that children have similar personality traits to their parents, those of which that are gene traits and are passed down. Another point you can look at is evolutionary psychology. As we evolve as a species, we acquire all different traits needed to survive. Certain traits, such as being a highly sociable species, have been passed down to help us survive. Along with that, we can look at Piaget’s stages of cognitive development to affect our behavior. Which every child will go through at a set time. With each stage being different, they all include things that a child and can not understand yet. First is the sensorimotor stage, occurring from age zero to two. Babies importantly learn what object permanence is, and by the preoperational stage they will understand it. 

With the preoperational stage, about ages two to seven, they will not understand conservation until the concrete operational stage. In the concrete operational stage, ages seven to eleven, children can not produce abstract thoughts. Such as, if they are asked a hypothetical question. They can not produce as complex answers as a child in the formal operations stage, ages 12 and beyond, unable to come up with what could hypothetically happen. Similar to that, we also go through what are called critical periods. These are set times in a persons’ life, where they have to learn a skill or else they will never have that ability to the same extent. Something that was largely debated was our ability to speech. There were two theories, either that there was a critical period for it or language learning was in our genes. The answer to this came with a young girl named Genie, who was deprived kept by herself and unable to learn most of her life. It was found that language does have a critical period, as Genie was only ever able to learn single words and could never form an intelligible sentence. All of the set stages we have in our life, are wired into us and essentially set a program for how our behavior is going to develop.

Some of the most supportive pieces of evidence come from what are called twin studies, studies done on identical or fraternal twins, or taking a look at twins in general. One twin study that gave great insight to how nature affects personality, was performed at the University of Minnesota started in 1979. It was focused on twins who were separated at birth, compared to twins kept together. The study proved that separated twins had the same chance of being similar to those who were not. This was split into different sections to discuss the evidence. The first section was an explanation on how they tested the correlation between genetic and environmental influences, the second section explained the details and results of the first section, third section focused on how IQ affects separated monozygotic twins, while the fourth section focused on this with dizygotic twins, the fifth section similarities were discussed, the last three sections were focused on the conclusions of the study. Part of the study found that even if twins were separated at birth, it had no significant effect on what their IQ was. 

A big question was whether or not separated twins meeting several times had an impact on IQ similarity, but after comparing the frequency of twins meetings, it was concluded that it did not. It was shown in the study that twins who were separated had similarities in behavior, religion, interests, and intelligence. There is a popular story of two twins, James Lewis and James Springer, who were separated after birth and adopted by different families. When they were reunited at the age of 39, they began to find striking similarities with each other. Including marrying women with identical names, also having the same name for their childhood dog, and similar names for their sons. Not only that, but they shared a lot of the same habits and went into the same fields of work as each other. For example, both of their first marriages were with a woman named Linda and then divorced to marry a woman named Betty. These studies that give evidence to show even twins who are separated early on, and raised in different environments have similar personalities, mannerisms, interests, etc. They truly prove, and shed most light on how much of an effect nature really has on us.

With the nature versus nurture debate going on for around 150 years, there has always been the question of which one affects our personality and behavior. Though in more recent years, it has been accepted that both of them have an influence. Taking this into account, we can raise the question of which has the greater effect. Which can ultimately be concluded to be nature, and not nurture. There have been multitudes of evidence that can prove this. First you can look at the different parts of your brain and body, really taking into account how much it affects the way we act. Another important point is that our DNA may possess different genes for personality, and that there are stages in our life that essentially preprogram our behavior. The most influential piece of evidence is twin studies, especially those about separated twins. As even those separated at birth show striking similarities in all ways to one another. Proving that our personality and behavior, truly is something already ingrained into us.