Research round 2 – How is one’s personality formed?

Hi everyone!

This is my second round of research with my question “How is one’s personality formed?” For this round, I am going to be researching about how genetics(nature) and the environment (nurture) can have an influence on personality and how the two differ.



Nature vs Nurture


The nature versus nurture debate has been going on for a long time. It’s the scientific, cultural, and philosophical debate about whether human culture, behavior, and personality are caused by nature or nurture. Nature is the part of the debate that is genetic or hormone-based behaviors, traits,and dispositions, while nurture is more so the environment, culture, and experience part of it. (1)

Both nature and nurture can play a role in personality but some twin studies suggest that genetics( or nature) is stronger. For an example, one study known as the Minnesota Study of Twins Reared Apart studies 350 pairs of twins between 1979 and 1999. The participants were sets of both identical and fraternal twins who were either raised together or apart. The results were that the personalities of identical twins were very similar to each other whether they were raised together or raised apart, which means that at least some aspects of personality are caused by genetics.Even though those were the results, it does not necessarily mean that personality is always caused by genetics, because there is definitely an environmental factor. Twin studies show that identical twins share about 50 percent of the same traits, while fraternal twins share only about 20 percent.(2)There was also an adoption study that compared biologically related people, including twins, who were either raised separately or apart. There was evidence that the genetic influence on a trait is found when children who have been adopted show traits that relate and are similar to  their biological parents than to those of their adoptive parents. The evidence for environmental influence is found when the adoptee is more like his or her adoptive parents than the biological parents.(3)


Personality would not be determined by any single gene, but rather many genes working together. There isn’t a “IQ gene” that determines intelligence. But even if they are working together, genes are not so powerful that they can control or create our personality. Some genes cause an increase to a given characteristic and others work to decrease that same characteristic; the complex relationship among the different genes, as well as a variety of random factors, produces the final outcome. Genetic factors always work with environmental factors to create personality. Having a given pattern of genes doesn’t always mean that a particular trait will develop, because some traits might occur only in certain environments. For an example, a person may have a genetic variant that can possibly increase their risk for developing some illness from smoking. But if that person never smokes, then that illness most likely will not develop(3)









For my next round, I wanted to look into personality disorders-

  • How/ why are they formed?
  • What effects do they have on the individual? 
  • How do they affect one’s personality change and development over time?

If you have any comments, questions or ideas, feel free to let me know. Thanks for reading!

3 Replies to “Research round 2 – How is one’s personality formed?”

  1. Hi Rhea, great round of research. I had no idea that twins raised by 2 different families could still share a lot of personality traits. I have one question though, how come siblings who we born and raised by the same parents have such different personalities?
    Here are some links that may help:

    OI look forward to your next round of research, hope these links can help. Good luck

  2. Hey Rhea,
    Interesting facts about nature and nature! I found your relation to identical twins raised in the same environment have similar personalities compared to twins who were raised separately very intriguing. Your next round on personality disorders will be very beneficial to tying the concepts together. Perhaps continuing with the example of twins could be interesting because they could have different personalities due to disorders that aren’t evident or certain genetic combinations lead to specific disorders. Overall for the bigger picture, I believe the discovering different personalities and understanding the development of them will be useful for many careers such as teachers, doctors and many more. Here are some links for your use in the future.

  3. Hi Rhea,
    Great round of research! You organized your information well, making it easy to read, and I like how you explained the “nature vs nurture” debate and how the roles in forming personalities of both genetics and environment are intertwined.
    I’m eager to read what you discover about personality disorders. One thing I noticed while searching for information on the topic is that personality disorders seem to be separated into different “clusters.” Therefore, it might be interesting to look into what shared characteristics personality disorders must have to be in a certain “cluster,” and what some examples are.
    Here are some websites I found that I think you will find useful in your next round of research:
    Good luck!

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