Are our personalities determined by genetics or do our experiences shape us?

In my philosophy class, we’ve discussed two different theories of development: the continuous model and the traumatic model. The continuous model states that who we are as adults is exactly who we were as children – just physically grown. The traumatic model takes more of a Freudian perspective in that it posits that who we are is a reflection of the traumatic experiences we had as children. This discussing had me wondering. Is there any truth to either of these models? Is it possible that both are true, or perhaps even neither? What makes us who we are?

To begin my search I conducted a Google search of my question. Through this search, I came upon a few different studies. The first, as reported in the New York Times, cited a study conducted by the University of Minnesota. The results of this study found that personality traits are mostly inherited. From 1979-1986, 350 twins pairs underwent various forms of testing, ranging from drawing blood to taking a personality evaluation test. The conclusion of the study found that more than half of the test personality traits were hereditary, as opposed to due to the person’s environment. This is further backed up when considering that out of the 350 pairs of twins studied, 65 pairs were raised apart from each other. Yet, their personalities were still remarkably similar.

The next study I found, from Edinburgh University, corroborated the first study’s findings. The university studied more than 800 sets of identical and fraternal twins in order to determine what effects nature or nurture has had on these peoples’ success in life. The participants were asked a series of questions which were then analyzed to determine the traits of the people studied. The results found that identical twins were twice as likely as the fraternal twins to have the same traits, which suggests that DNA has a strong impact on personality. It is wise to remain skeptical though, as we have learned in class that correlation does not equal causation.

Although the two studies seemed credible, I wasn’t yet convinced. I tried to find evidence of a differing scientific opinion, however, I was less than thrilled with my discovery. Researchers at the University of Exeter and the University of Hamburg determined that environment plays a stronger role in shaping personality than genes, however, their study dealt with zebra finches and not humans.These finches were taken from their birth parents and placed in a foster environment. Researchers found that these foster finches had more of an influence on their children than genetics seemed to. Personality was more dependent on environment for these birds than genetics, although researchers did acknowledge that offspring size of these finches did seem to be genetically inherited.

Overall, it seemed that through the various studies I found, some not included in this post, corroborated the idea that personality is largely genetically inherited. However, this clearly isn’t the only thing that defines one’s personality. It is such a complex thing that encompasses many factors, so it is impossible to say conclusively in any of the studies that genetics is that only thing that makes up someone’s traits.

4 thoughts on “Are our personalities determined by genetics or do our experiences shape us?

  1. Jon Shanfelder

    Reading your article and the results came as quite a shock to me. Everything in my academic career has confirmed the opposite. That personality and who we are as a person is somewhat genetics but mostly shared by our environment. So I did some digging into your studies and not only did they not come from credible sources, but the experiments in the news articles held very small sample sizes. They did not report a p-value but I’m sure it was very high because to make a generalization that big is absurd in science. Here is a more credible source that says otherwise:

  2. dms6679

    I feel that both arguments make valid points, but I personally feel as though genetics plays a bigger role in determining personality. For example, my older sister and I both grew up in drastically different environments, given that my mom had her earlier in life. Nevertheless, even though it seems that I grew up in a more favorable environment, my sister and I have extremely similar personality traits. In saying that, I do feel that our environments shape our views on things, but not our personalities as a whole.

  3. tmv5147

    I feel both sides are correct. For instance, I’m sure all of us have been in a situation where one of our parents and/or reletives have used the line “you are such like your mother/father.” Obviously we want to create our own self image and no one likes being compared to someone that they are not. You can’t take away from the fact that you are like your parents in some way, you look like, you may act like them, you may share the same intresets. That’s all backed by science in some way. Expierences are also big factors in how your personality is shaped, a rational person should understand this. If you are a procastinator, and you know if you are, you leave everything until the last possible minute and then you decide to do it. A decent amount of time, when you get the feedback from that assingment that you left for the last minute, it’s usually not great feedback. Now sometimes people are busy and they don’t have time to get to it, it happens to everyone. But you’re going to want to avoid that in the future so you don’t have to cram and end up getting a bad grade.

  4. Wencong Wang

    Thank you Sarah! I always want to know what determine our personality. I always think the enviroment determine our personality more than genetic factor does. Because, we always say your living enviroment decide who you are. A guy live around bad people is hard to be a good person, because the bad people’s idea will conduct to this guy and shape his/her mind, in addition to affect his/her personalities. So, I think the genetic things may not be the main factor of personalities. We can see lots of people’s personalities are far different from their parents. Here is a fun video I found that talks about the travel will shape your personalities.
    Hope you like that!

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