My sister and I are two years apart, but we are like twins. Ever since we were young, we were best friends and stayed together for 18 years until she left to college. Even though we didn't look very similar, we had same personalities. We both were introvert and shy when we met new people.
After my sister and me both moved to America, our personalities started to change. We both did not notice how much we became more outgoing until we visited Korea two years ago. My relatives and friends were surprised when they saw us because we were so different. When we were young, we had a family party during Christmas. When all of my relatives gathered together, my sister and I were timid to talk to people and shuttered the answers when someone asked questions. We stuck together whole day and followed my parents around. This shows how much we were not socially engaged.
However, now we both have a lot of friends and we talk to people easily even at the first time. We don't get timid by crowd or people anymore. As I compare myself from the past and now, I think the environment changed our personalities. When we lived in Korea, I grew up under my typical Asian grandparents. They were very conservative and valued Korean traditions. They did not allow us to hang out with friends outside. We always had to study, and wear neat clothes that do not show our bodies a lot. However, when I started to live apart from them after we moved to America, my sister and I started to change. We followed more American culture and made different types of friends. They were more outgoing and talkative than my friends from Korea.
When I was reading the text book about nature and nurture, this came to my mind. Why did my sister and my personality change so suddenly? Did environment affect our personality? Or were we born with our extroversion? Which more affects people's personalities?