Nature vs Nature

Nature vs. Nurture

Psychologists have often questioned whether personality traits are inherited,
and therefore a result of genetics, or if they are caused by the environment,
and are therefore made. This has come to be known as the nature versus nurture
controversy. Many psychologists throughout history have asked this question, and
most agree the answer is both.

Nature versus nurture has been an on going argument for over a century and
will carry on further. Scientists have been unable to conclude this question of
which carries most responsibility for behavior. The argument of nature versus
nurture is examined through the role of genetics in one’s personality. Then
the role of environment in a one’s personality. Finally showing how both
nature and nurture coincide to influence behavior in children, that the genetic
makeup shapes one’s personality, thus determining how their environment is

Though one’s personality is not determined strictly by genetics, there is
more evidence to support the idea that personality is inherited than there is to
support the idea personality is made based on the environment and based on one’s
experience. Many experiments and studies have been done to determine where one’s
personality stems from, yet, few studies have been as effective as those studies
based on twins, and adopted children. Both types of studies are extremely
successful in determining where one’s personality comes from. In a twins
study, the genes are regulated while in an adoption study the environment is
regulated. Thus, question comes of introverted and extroverted personalities.

One who is introverted is often thought to be someone that keeps to himself
and rarely chooses to socialize in large groups. He is thought to be a longer
and in many cases to lack the social skills necessary to enjoy himself in
situations that are new to him. In reality, someone who is an introvert is
simply more affected by stimuli than someone who is an extrovert. While an
extrovert may be able to study in a noisy environment with many interruptions
and distractions, an introvert is more likely to opt for a quiet corner of the
library, free of extemporaneous noise.

A study was conducted that tested identical adult twins pairs that had been
raised living apart from one another (Plomin, 1993). The twins were given self
report tests to rate the extent to which they felt that they had grown up in an
environment that was based around acceptance or rejection. In addition to
testing these two traits, the extent to which their parents disciplined the
twins was also tested. The reason for the self report tests to be centered
around these topics because Plomin thought that it was important to determine a
correlation between the environment one is raised in, and one’s personality.

Plomin tested 59 pairs of identical twins reared apart and 142 pairs of
fraternal twins reared apart. What Plomin discovered was that traits once
thought to be created based on the environment that one lives in, are really “influenced
by genetic factors” (Plomin and Bergman, 1991). Many of the twins studied were
said to have similar personalities, yet because they were raised apart, the only
basis for the similarity is a genetic one. Though the twin studies were
successful in proving that personality is in fact genetically based, many
scientists were not convinced that one’s genes are the only factor that create
one’s personality. Because “twins share the same womb, birth date and
family, many possible environmental confounds were controlled” ( Plomin 1993)
thus making adoptive studies a more accurate assessment of the inheritance of

It has been hypothesized that adopted twins raised independent of their
parents will develop a personality more similar to their adoptive parents than
to their birth parents. The reason for this hypothesis is that many people
assume that one learns who is and how one should act from the people living
around them. Through extensive studies, Plomin (1993) was able to discern that
adopted children are actually more similar to their birth parents than to their
adoptive parents. Additionally, adopted twins reared apart are more similar to
one another than similar to their adopted siblings. Though scientists have been
able to conclude that genes do effect behaviors and personality, the question
still remains what genes effect what behaviors.

Studies that look at the influence of genetics and environment on personality
use of the concept of genetic similarity of siblings. By examining genetic
similarity one can look at the differences in siblings as they grow up, with the
knowledge that the subjects came from similar genetic backgrounds. Lynn, Hampson,
and Agahi (1989) found support for the idea that traits are inherited in a