Human behavior and the development of personality traits has always puzzled psychology researchers and scholars: “The development of individual differences has always been a primary focus of psychological research, and it continues to be an intensely debated topic to this day” (Giudice & Belsky 2010, p. 154). Retrospective analysis of personality is widely used to examine the development of various traits throughout life; however, it has many severe limitations and thus is not considered a valid academic research method (Gleitman, Gross, & Reisberg, 2011). Changing Traits: Nurture Looking back at my own life history, I realize that a lot of my personality traits have changed through the years. With changes to living conditions came the necessity to adjust to the new environment, particularly through the changes in personality and behavior. The traits that change in response to the environment are said to be under the primary influence of nurture (Gleitman et al., 2011). For instance, as a kid, I used to be very naïve and trusted everyone I met. I did not expect people to cheat, lie, or to betray me in any way. However, as I gained more experience in communication and in dealing with other people, I became a lot warier. After one of my best friends had betrayed me several years ago, I became rather distant and secretive, and now it takes a long time before I let a new person into my private life. Another change occurred when I started living apart from my family and earning my own money. Most of the families teach their kids to share and be generous; however, they teach children to share the things that are not exactly theirs, since the kids did not buy or earn them. As soon as I started living on my own, I became a bit more reserved about lending money to friends or paying for a shared meal at a restaurant. Parents also teach their children to seek approval from the society, be it other kids at school, family elders, professors, and so on. I used to be very dependable on other people’s opinions of me. I used to get anxiety whenever I met new people, as I was worried about what they would think of me. I refrained from speaking my mind or dressing the way I wanted if I felt like the society would not approve of my looks or actions. As I grew older, however, I came to terms with myself and became more independent. I am no longer afraid of doing the things I want, and I do not need the approval of others to feel confident about myself. Stable Traits: Nature Some of my personality traits, however, remained the same since childhood. For instance, I used to be very creative and artsy as a kid, and this feature still applies to my present personality. Other unchanging characteristics include kindness, intelligence, and curiosity – they have been present in my character for as long as I can remember. Scholars who stand on the side of nature believe that the unchanging qualities are innate or, in other words, depend on biological or genetic predispositions (Giudice & Belsky, 2010), which is why they are not affected by environmental conditions. Most of these qualities were chosen as desirable by evolution: for instance, intelligence has always been one of the key favorable characteristics in natural selection (Gleitman et al., 2011); others, howe