What twins can teach us about nature versus nurture?
Twin studies are used to clarify the influence of nature versus nurture in different traits and disorders. Having shared identical environments for 21 years, and the same genes since birth, we are of interest to medical science. After all, if we are such clones of each other, why do only I wear glasses?
How are twins help us understand nature and nurture?
When researchers seek to determine how personalities are developed, many look to twin studies to see how relative factors such as nature (genes) and nurture (environment) influence or dictate the way behavior and traits are established. The case centers on the dispute of what exactly drives us to be us.
What are your beliefs on nature versus nurture?
The nature argument places more of an emphasis on genetics in how humans develop. The nurture argument credits how someone was raised or the environment they live in to be more impactful to human development. What is more influential, nature or nurture?
Why is nurture better than nature?
Nurture has a larger effect on us than does nature. Nurture is the characteristic builder that we gain as we grow up. It is what defines our nature and makes us who we are. Nurture cultivates our nature, and it is the main regulator of our being.
Why are twins important to scientists?
Twin studies have been an integral part of science because of the unique genetic similarities between twin siblings. Identical twins develop from a single fertilized egg and they have the same genome. This means that any differences between the twins are due to their environment, not their genetics. For nearly a century scientists have used twin studies to better understand the extent to which certain traits are inherited.
What percentage of twins' traits ended up being the cumulative effect of genetic differences?
In about 69 percent of the cases, the twins' individual traits ended up being the cumulative effect of genetic differences. “This means that there are good reasons to study the biology of human traits, and that the combined effect of many genes on a trait is simply the sum of the effect of each individual gene,” Benyamin explained.
Is bipolar disorder genetic?
For example, in the case of bipolar disorder, this was found to be around 70 percent genetic and only 30 percent due to environmental factors.
Is it 50/50 nature versus nurture?
The experts agree that overall it's 50/50 when it comes to nature versus nurture. Photo courtesy of Shutterstock
Is the variation for human traits and diseases split almost equally?
The impressive global twin review revealed that, on average, the variation for human traits and diseases is split almost equally . “When visiting the nature versus nurture debate, there is overwhelming evidence that both genetic and environmental factors can influence traits and diseases,” Benyamin said in the press release.
How do twins help us understand nature?
As identical twins, 19-month-old Sol and Luna share 100 percent of the same DNA. Both girls have soft oval faces, tufts of curly brown hair, slight noses, and large almond-shaped eyes. If Sol’s coat is taken off, Luna will notice, and she will eagerly mimic for hers to be removed.
Why are twin studies important?
Twin studies help decide the impact of predisposition and determinism.
Why do some researchers study twins that have been adopted into separate homes?
Just because twins share the same DNA, will they both automatically be as studious as their mothers or as gregarious as their fathers? Are we born with a blank slate that is only molded through environment, or do genes decided what type of person we will ultimately become ?
Why do some twins have variance?
However, the variance in some twins is so profound that many researchers are pointing to a third element at work: epigenetics, the study of inherited changes in phenotype (appearance) or gene expression caused by mechanisms other than changes in the underlying DNA sequence. For example, one can be influenced by lifestyle and diet. Some researchers are also looking at epigenetics to explain exactly why some twins start out with the same characteristics but dramatically diverge as they age; and perhaps why one twin might suffer from an illness while the other is not affected.
How old are identical twins?
Manel Esteller of the Spanish National Cancer Center in Madrid, studied 80 pairs of identical twins ranging in age from 3 to 74.
Who was the child psychologist who believed in the nature versus nurture theory?
In the 1960s, child psychologists Dr. Peter Neubauer and his colleague Dr. Viola Bernard, also a child psychologist and consultant to the Louise Wise adoption agency in New York, sought to find an answer to the impasse of the “nature versus nurture” theory. Both doctors strongly believed that twins should be raised separately and used the adoption agency to conduct long-term studies of twins and triplets in order to see how each individual would develop without the interference of being treated exactly the same, by the same guardians.
Who said that genetics and environment are important for behavioral development?
Dr. Scott Barry Kaufman , a cognitive psychologist and popular science writer, says that both genetics and environment need to be considered when trying to understand behavioral development. “There always is a dynamic interplay between our genes and our environment. Genes aren’t deterministic things; they are entirely there to help guide us to choice. If our genes didn’t influence us at all and we were completely at the whim of external forces, we would never make any of our own decisions, we would never have any of our own inclinations.”
What is the difference between twin A and twin B?
Twin A, who had been pushed against an unyielding pelvis for several hours, spent most of his first day alert and looking around, while Twin B , who had been spared this pre-birth stress, slept calmly like a typical newborn.
Who wrote the book Twin Misconceptions?
Dr. Segal, who has also written “Twin Misconceptions: False Beliefs, Fables, and Facts About Twins,” said the studies highlight the importance of keeping twins, especially identical twins, together when they are adopted. As was depicted in the documentary, Dr. Segal said, “The triplets deeply resented having been separated.
Why do scientists want to alter gene expression?
Researchers are seeking ways to deliberately alter gene expression in hopes of finding preventives or treatments for diseases like diabetes with a strong genetic component. There can also be changes in the genome of an identical twin when the egg divides, resulting in a defect in a particular gene, Dr. Segal said.
What are the environmental factors that affect epigenetics?
Epigenetics influences which genes in an individual’s genome may be turned on or turned off. Such factors as exercise, sleep, trauma, aging, stress, illness and diet have been shown to have epigenetic effects, some of which can be passed on to future generations.
How much of the variation in I.Q. is genetic?
The studies of reared-apart twins have shown that in general, half the differences in personality and religiosity are genetically determined, but for a trait like I.Q., about 75 percent of the variation, on average, is genetic, with only 25 percent influenced by the environment.
Does genetics influence sexual orientation?
A study of 4,000 pairs of twins in Sweden found that genetics has a stronger influence on sexual orientation in male twins than in female twins. As I observed in my own sons and know from studies of heart disease, genes confer a potential, but the environment often determines whether that potential is expressed.
Why are there twin studies?
Twin studies have been around for a long time due to the genetic marvel that lies within the siblings. However, some cases of these studies are mind boggling and some argue inhumane. In the Secret Sibling case, Doug Rausch and Howard Burackand had both been adopted through Louise Wise Services in the 60’s. ABC News reports that George Rausch was told he would not be able to adopt Doug if he couldn’t participate in a study. After he agreed, the adoption agency gave them their new son. Both Rausch and Burack and their families reported mysterious researchers coming to their homes to conduct tests, interviews and film the boys in their childhood. Doug Rauch told “20/20” that they even filmed him riding his bike. The families reported the researchers visiting the boys for a decade. It wasn’t until the twins were grown adults when the truth was exposed. At the closing of the Louise Wise Services, a guilty woman dying of cancer called Doug to reveal that he had a long lost twin. Eventually they met and were able to rekindle their relationship. It turned out the researchers were conducting a study on nurture vs. nature and using the boys as human test subjects. After the truth was displayed for the public many people thought the study was inhumane. To separate siblings, let alone twins at birth changed their lives. That’s the difficulty when exploring nature vs. nurture on twins, there’s not a way to do it accurately without having to go that extra step and isolate them from one another.
Why do scientists use twins?
Scientists and psychologists use twins to explore this debate because of the genetic similarity between the siblings. Infamous cases like the Jim Twins and the Louise Wise Case help scientists learn even more about the influences of environment and genetics. With twins ourselves, we are interested in understanding how twins play a part in ...
Why are boy and girl twins more likely to have differences?
For a boy girl twin pair, it is more likely that they will have more differences because the expectation that twins are the same is not as great. People don’t expect boy and girl twins to be similar which is why genetics play less of a role.
Why are identical twins relevant to this argument?
Twins are relevant to this argument because they grow up in the same environment. The whole argument against the influence of nurture is that twins, fraternal or identical, grow up in the same environment.
What is nurture in genetics?
The term nurture refers to the environment in which children grow up in.
What are the two types of twins?
There are two types of twins: fraternal (dizygotic) and identical (monozygotic). Fraternal twins result from two different eggs and therefore share only 50% of their genes. Identical twins result from one split egg which is why they share 100% of their genes. This difference is important because identical twins are more likely to be affected by ...
How old were the Jim twins when they were adopted?
In 1940, two twin boys had been put up for adoption and their adoptive parents named them both James at just three weeks old. As they grew up 40 miles away from each other, the list of their uncanny similarities continued to grow.