Mental Health - Nature vs. nurture: does biology or environment influence development?

Mental Health Nature Vs Nurture Does Biology Or Environment Influence Development 2466
Photo by: Jan Will

The nature vs. nurture debate revolves around the following question: what factors contribute to the mental development of an individual: nature (that is, the biological or genetic makeup of a person) or nurture (that is, how a person is raised, by whom, and in what environment)? Just as human beings inherit certain physical traits from their biological parents (such as height, eye color, and even predisposition to physical ailments), human beings can also inherit certain mental characteristics and traits from their parents, such as a propensity for certain mental disorders. What else is inherited and what traits and characteristics develop as a result of the environment in which an individual is raised? Some researchers believe that things such

Mental Health: Words to Know

Alzheimer's disease:
A degenerative disease of the brain that causes people to forget things, including the people in their lives, and which eventually leads to death.
Being in charge of oneself; independent.
Classical conditioning:
Learning involving an automatic response to a certain stimulus that is acquired and reinforced through association.
Convergent thinking:
Thinking that is driven by knowledge and logic (opposite of divergent thinking).
One's capacity to think and solve problems in a unique way.
Divergent thinking:
Thinking driven by creativity (opposite of convergent thinking).
Eidetic memory:
Also known as photographic memory; the ability to take a mental picture of information and use that picture later to retrieve the information.
Being outgoing and social.
Identical twins:
Also called monozygotic twins; twins born from the same egg and sperm.
Inborn; something (a characteristic) a person is born with.
The ability and capacity to understand.
Intelligence Quotient (IQ):
The measure of intelligence as based on intelligence tests and the intelligence of the general population.
Being quiet and soft-spoken.
Modifying behavior and acquiring new information or skills.
The ability to acquire, store, and retrieve information.
Learning based on modeling one's behavior on that of another person with whom an individual strongly identifies.
The biological or genetic makeup of a person.
Nerve cells that receive chemicalelectrical impulses from the brain.
How a person is raised, by whom, and in what environment.
Observational learning:
Learning from the examples of others.
Operant conditioning:
Learning involving voluntary response to a certain stimuli based on positive or negative consequences resulting from the response.
All the traits and characteristics that make people unique.
Making something stronger by adding extra support.
How an individual feels about her or himself.
Something that causes action or activity.
Gaps between nerves; the connections between neurons that allow people to make mental connections.
How people behave.

Time will tell which traits—physical and mental—this father has passed along to his son. (Photograph by Robert J. Huffman. Field Mark Publications. Reproduced by permission.)
Time will tell which traits—physical and mental—this father has passed along to his son. (Photograph by
Robert J. Huffman. Field Mark Publications
. Reproduced by permission.)

as alcoholism or even intelligence are biologically inherited while other people support the theory that many of these things are a product of the environment in which an individual is raised.

Many studies in the nature versus nurture conflict center on identical twins. Researchers look not only at twins raised together but those raised apart to determine whether or not a certain trait is biologically programmed or if it evolves as a result of the environment in which one twin was raised. However, a flaw in research of this type is that, often times, the twins who had been separated by adoption were raised in very similar environments.


The most controversial area in the nature vs. nurture debate is intelligence. The reason for this may be that intelligence (which is a person's capacity to think rationally and deal with challenges effectively) is closely related to achievement, both scholastic and in other situations. While most researchers agree that intelligence is influenced by genetics to a great degree, studies show that twins of all kinds and biological siblings are more likely to possess similar intelligence. In fact, the closer the biological link, the stronger the similarity in intelligence. However, there are also similarities in intelligence between unrelated children raised together in the same household, though these similarities are not as great as those between biological siblings and, especially, twins.

What this and other similar research says is that no one definitive factor solely affects intelligence. The manner in which an individual is raised greatly influences one's intelligence. While one researcher, psychologist Arthur Jensen, put forth that intelligence is 80 percent determined by biological factors, other researchers have settled upon figures

This young man has been encouraged by his parents to read the newspaper each day, thus boosting his intelligence. (Photograph by Robert J. Huffman. Field Mark Publications. Reproduced by permission.)
This young man has been encouraged by his parents to read the newspaper each day, thus boosting his intelligence. (Photograph by
Robert J. Huffman. Field Mark Publications
. Reproduced by permission.)

ranging between 50 and 70 percent. This means that whatever an individual's natural intelligence, it can always be improved or obstructed by his or her environment.


In addition to physical characteristics and intelligence, researchers have also tried to determine whether genetics or the environment influences an individual's personality. If a really outgoing, social individual has a child, will that child also be outgoing? Some researchers say yes. In fact, scientists have been able to prove that there is a biological relationship in terms of personality where extroversion (being outgoing and social) and neuroticism (being touchy, moody, or overly sensitive) are concerned.

How can this be proven? Through studies involving twins living apart. In fact, similar studies have found that many things seem to be inherited—from values and political attitudes to the amount of time people spend watching television! This may sound silly and, of course, no one is suggesting that a specific gene has evolved that directly influences a person's preference for watching television. Rather, what researchers are focusing on is that the act of watching television is usually a solitary, passive one. This could be something that is tied to whether or not a person is extroverted. Findings of this type are also confirmed by the fact that scientists have identified a gene that affects brain chemistry and may be the reason that certain individuals engage in risk-taking behaviors, such as bungee jumping or extreme sports, while others do not.

Mental Disorders

As discussed in Chapter 12 on Mental Illness, schizophrenia (a serious psychological disorder marked by scattered thoughts, confusion, and delusions) has been found to have a high genetic correlation, meaning that if one family member has schizophrenia, there is an increased likelihood that another family member (or future offspring) may also develop it. Of course, while an individual may be predisposed to schizophrenia because of genetics, that is not to say that he will ever develop the disorder. Other psychological disorders that may be hereditary include alcoholism and major depression. [ See Chapter 12: Mental Illness.]

Most researchers now agree to some extent that both biology and environment play important roles in shaping people. Just as children may share traits with biological parents, adopted children may also share many traits and habits with their adoptive parents. What this information serves to do is help mental health professionals, teachers, and researchers help all people realize their potential for growth and accomplishment in their lives.

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