Download To what extent does genetic inheritance influence

To what extent does genetic inheritance influence behavior?
For years and years, there has been endless debating on whether human behavior is
predetermined by genetic inheritance. The question that behavior was due to the
transmission of genetic material from parents to offspring or construction by the
surrounding environment had one of humanity’s greatest mysteries (medpdia).
However psychologists and scientists have finally concluded that human beings are a
product of combination of nature and nurture. No longer does any researcher with
any reputation claim one over the other, it has now become a question of how much.
Genetics definitely do influence our behavior, but to what extent? Trying to solve this
question, psychologists and scientists look towards research on twins for clues. The
main feature of these studies is that identical twins share the same genetic
inheritance. Therefore, this allows psychologists and scientists to analyze the
difference in twins’ behavior and conclude which of two: genetic inheritance or
environmental factor, have influenced their behavior the most. Supported by the
studies of identical twins’ similar IQ scores and sexual preferences, genetic
inheritance influences behavior to large extent.
The study of twins in the psychological world today elucidate the best clues into how
genetics influence behavior. Researchers enthusiastically seek out twins that have
been separated from birth to study their similarities and differences. Thomas
Bouchard from the University of Minnesota has conducted studies on over 8000 pairs
of twins some identical and some not.
According to Thomas Bouchard’s twin studies, which tested the twins’ Intelligence
Quotient (IQ), intelligence is “69-78% heritable”, concluding that since IQ is heritable
more than 50%; therefore, genetic inheritance influences human intelligence as well
as their behavior to large extent.
Intelligence is an integral component of how our brain operates, and the fact that it
can be heritable raises serious questions about how we can develop it. Moreover, a
case study on the twins Ms.
Herbert and Daphne by Bouchard illustrated that although they were separated in
early stage of their life, they showed remarkably similar personalities and
mannerisms (Bouchard, IQ studies). Even though Ms. Herbert and Daphne were both
brought up in different environments under different step-parents, the fact that they
possess similar characteristics to each other concludes that genetic inheritance to
large extent determines human behavior. Therefore, the twin studies and the case
study on Ms. Herbert and Daphne supports the conclusion that although
environmental factors do effect human behavior as well, genetic heredity plays a
massive role in our development in personality or characteristics.
Intelligence however, is just the beginning to understanding how truly heritable traits
of our minds are. Studying human sexual orientation is an integral part of our
understanding of genetic influence. If we truly are products of our genes or
environment, how much of what designates our sexuality in the future? According to
the case study on Australian identical twins, homosexuality was 20% heritable in men
and 24% in women. Moreover, National Cancer Institute researcher reported that
“many homosexual men appear to inherit a gene from their mothers that influences
sexual orientation”. Adding to this report, Dean Hamer, the chief of the cancer
institutes's Section on Gene Structure and Regulation, claimed that “people have no
control over the genes they inherit and there is no way to change them” implying that
homosexuality is not a choice or a simple decision but determined by the genetic
inheritance. Studies on the family histories of 114 gay men showed that there were
more homosexual brothers, uncles and male cousins than the general – heterosexual
– population. Like the twin studies, mentioned in previous paragraph, these studies on
homosexuality in a family contain the feature that these relatives or members of a
family share common genetic inheritance but were raised in different environment.
Although these members of a family were brought up from different environment
and have different personal experience, they share the common genetic inheritance
which, in this case, is homosexuality. To the question of where homosexuality mainly
comes from, it can be answered that members of a family and twins as well as
relatives, tend to have similar characteristics including sexual preference.
Therefore, supported by the studies of homosexuality further supports the concept
of heredity affecting our behavior.
However, it is important to note the other side of the spectrum as well in this longstanding argument. The value of environment and development through age is just
as critical as their heredity. Although studies of twins’ IQ support the argument: to
large extent genetic inheritance influence, similar outcome is resulted from studies of
adopted children who have no blood relations with their step-parents, meaning that
they have different genetic inheritance.
Although the adopted child does not share any common genetic inheritance, his IQ
scores are related to the step-parents. Moreover, it is critical to note that although
genes do affect behavior, it may not be expressed due to the environment. If genes
do cause homosexuality, than in a society where homosexuality is taboo, it would not
be shown and therefore never accounted for. In addition to IQ or sexuality, other
aspects such as religion, interests and hobbies are only some of which that differ
from person to person no matter their genes. Thus, while to large extent genetic
inheritance influence human behavior, we should keep in mind that environment is
also a critical factor. To even understand the impact of heritability, environment is a
critical part that needs to be analyzed. Even traits that are highly heritable are open
to changes. Experience can modify anything in our lives. Although you may be
naturally impulsive or rash, years of learning how to control yourself
and calm
parenting may cause you to be calm and collected. It is also critical to note that
although genes do affect behavior, it may not be expressed due to the environment. If
genes do cause homosexuality, than in a society where homosexuality is not
accepted, people would suppress and hide it. Although genes play a large role in
determining our behavior, it is without a doubt that environment does as well.
Overall, while human beings are product of both genetic inheritance and
environmental factor, to large extent genetic inheritance influences behavior more
than environmental factor does.
Supported by the twins’ IQ studies and homosexuality studies, it is concluded that
despite the research participants, separated identical twins were raised from
different environment, showed similar behavior since they share the common
genetic inheritance. One of the most critical questions of our time, discerning the
human mind’s behaviors is only the gateway to unlock new potentials in humans or
curing psychological illnesses. It will still take years of learning for us to truly decode
how much of one’s brain in influenced by nurture or nature.