Genetic Research and Biological Theory
How do we go about determining if a trait, a temperament, or a personality feature is inherited through biology or the environment? This question has been answered in part through genetic research. Genetic research, in relation to personality development, refers to studying the role of genetic and environmental factors through manipulation or convenience. In other words, studying fraternal twins raised apart would provide important information related to inherited traits. Studying adopted siblings not related through biology would allow us to look at the environmental factors that shape personality.
Obviously ethical considerations do not allow researchers to manipulate a child’s environment to this degree, so the subject pool for such research is slim. Also, because these studies can be so time consuming (e.g., studying one child over a period of years), information is often gathered after the fact.
Through this type of research, however, we have realized some important information. By determining correlations between twins raised together, twins raised apart, and adopted siblings, we have found some fairly strong support that some of our personality is actually inherited. Among the areas found to be related to biology, at least to some degree, are intelligence, introversion-extroversion, and neuroticism.
Trends in Biological Theory
Like many aspects in the measurement of human differences, the study of personality has come full circle. The ancient beliefs about the inheritability of personal characteristics was replaced with more modern theories of environment, socialization, parenting styles, and sexuality. Today, biological components of personality are again gaining influence as more advanced medical techniques are developed. New discoveries such as those propelling DNA studies are fairly new but they open up a whole new area of knowledge in the relationship of genetics and personality.
It is doubtful that we will be able to quantify the biological components of our personality. Like all areas of psychology, absolutes are few and far between, and it is impossible to completely eliminate subjectivity. We are, however, focused again on the role of biology, and even evolution, as we continue to explore the development of human personality.