In Chapter 14, we learned about Personality. Personality is defined in lecture as "Distinctive, characteristic patterns of thought, emotion, and behavior that uniquely define an individual" (Simpson, lecture, 11/14/2011). The textbook describes 3 broad influences on personality: genetic, shared environmental, and nonshared environmental factors (Lilienfeld, Lynn, Namy & Woolf, 2010).
Genetic factors are basically the genes an individual inherits from his parents. Environmental factors are experiences of the environment that an individual lives in and what makes him similar to his family. For example, if a family really enjoys sports, then they may require all of the children to participate in sports. The members of the family may be more competitive and aggressive than a family that is not as involved in sports. Nonshared environmental factors are those experiences that make him less like his family. For example, in this same sports centered family, one child may not be athletic. This child may feel left out of family activities or perhaps even not a part of the family. This could cause lower self-esteem in that child as compared to the rest of the family.
An interesting aspect of the nonshared environmental factors is the influence of birth order on personality. Many popular books claim that firstborns tend toward achievement, middle-borns toward diplomacy, and later-borns toward risk taking (Lilienfeld, Lynn, Namy & Woolf, 2010). Research has not supported an association. But the media has produced many reports that support (or perpetuate, depending on one's perspective or birth order) this idea. I have read that almost all of the U.S. presidents were either firstborns or firstborn sons. It has also been reported that firstborns had higher IQ's than their siblings and most CEO's are firstborns. The theory is niche partitioning. It is the idea that firstborns are more likely to be substitute parents for their younger sibling(s) (Reinberg, 2007). This makes them more independent and responsible. The other siblings must also find their own niche, and they will choose a niche that is a unique addition to the family. As a firstborn, I can relate!
Reinberg, S. (2007, June 21). To the first-born go the smarts. The Washington Post, Retrieved from http://www.washingtonpost.com/wp-dyn/content/article/2007/06