Q3
Describe the genetic and environmental origins of personality. Which do you consider the most important to the development of the adult personality? Why?
The famous psychologist Donald Hebb is said to have once answered a journalist's question of which, genetic origins or environmental origins, contributes more to personality? by asking in response, which contributes more to the area of a rectangle, its length or its width?( Herschkowitz and Herschkowitz, 2002) Traditionally, personality has been thought of as not only inherited but divinely ordained. The differences between men and women, for example, were attributed to God's design. Whole ethnic groups were considered to be, by nature (genetic origin), superior or inferior. In the 19th and 20th centuries, however, intellectuals increasingly attributed differences among races, classes, and genders to socialization (environmental origins), rather than to innate qualities (genetic origins).
Behavioural geneticists perform adoption and twin studies in order to disentangle the effects of genes and environment on personality. According to behavioural geneticists two different types of environmental factors affect personality. They are shared family factors that are those traits shared by siblings, making them more similar and nonshared factors that are those traits that uniquely affect individuals, making siblings different. In order to express the portion of the variance that is due to the genetic origins component, behavioural geneticists generally refer to the heritability of a trait.
With regard to the Big Five personality traits as well as adult Intelligent Quotient (IQ), the portion of the overall variance that can be attributed to shared family effects is often negligible (DeFries et al 2000). On the other hand, most personality traits are thought to be at least partially heritable. In this context, the genetic origins component of the variance is generally thought to be more important than that...