Effects On Heritability And Environment : Twin And Family Studies

Identical twins are many times seen as genetic reproductions representing variations from twin to the other twin and are created because of environmental factors (Cervone & Pervin, 2010). Since identical twins share identical genetics, his or her personality seems to also share similarities. Moreover, the environment can impact fraternal twins, resulting in fraternal twins personalities and his or her characteristics similar to each other. For example, identical twins. Some research shows twins that are raised in the same residence have little differences from those who are raised in a different home.

Human behavior is a loosely defined foundation for individuality, generally considered to be influenced and developed by the environment. However, recent molecular studies have exposed genetic factors that suggest a more biological origin for behavior. Gene segments in the genome of humans and other animals have been identified and associated with particular behavioral traits. Is it possible that the presence or absence of even a single gene may predispose one to alcoholism, increased irritability, or enhanced intelligence? Clearly exploration of the nature versus nurture argument with regard to genetic predisposition has social, political, and legal significance.

A person’s nature, or genetics, determines aspects of the psychology of a person before they’ve been born. There are many example of how genetics determine characteristics of a person, regardless of the environment, also known as

M. van Beijsterveldt, Meike Bartels, and Dorret I. Boomsma (2014) determined that knowing the effects of heritability largely depends on the way it is assessed and interpreted. Their information came from a variety of different sources, such as teachers, parents, and even self-evaluations. They discovered that the inconsistency in measurement was partially responsible for any particular behavior to seemingly fluctuate in its externalized degree, whether from person to person or the same person over time. Ultimately, Kan and his colleagues (2014) decided that heritability does have an influence on one’s externalized behavior, but that it is largely due to context, situation, or environment, although exact proportions of heritability cannot be calculated because of the inconsistency in measurement among various

Individuals within an environment have different traits; some of these traits are genetic and are passed on to offspring.

During the second half of the 20th century, psychology was dominated by the behaviorism theory which states that all human behavior is controlled by environmental factors. Adopted monozygotic twins who were separated at birth were to be reunited later on as adults. The purpose of this study was to see if monozygotic twins that were raised together (MZT) were more similar than monozygotic twins that were raised apart (MZA). The twins each had one week visit, testing about 50 hours every week. These tests included four personality trait scales, three aptitude and occupational interest inventories and two intelligence tests. Along with these tests, there were interviews that were held. These included a life history interview, a psychiatric interview and a sexual history interview. All the assessments that were done were held individually so that the twins did not influence each other’s answers.

In this essay which is called Heredity Versus Environment: Twin, Adoption, and Family Studies", Nature refers to heredity and nurture refers to environment. The main question answered in this article is what are the roles of the heredity and environment in the development of various human characteristics? Also, how can one determine the influence of heredity and environment for various human characteristics? It is not about whether either heredity or environment is responsible for observed outcome. He used reference from John Locke, Rene Descartes and Immanuel Kant.

In the modern age, genetics, the study of heredity and inherited characteristics, is a rapidly developing field of science which has provided major advances in the

Heredity – the transmission of traits from one generation to another, from parents to offspring; the protoplasmic continuity between parents and offspring

There are no two individuals that are completely alike, people vary by hair color, height, skin tone, gender and other endless possibilities. The reason for these variations can be traced back to our genetic make-up. A person as 23 pairs of chromosomes and each of these chromosomes carry one molecule of DNA. DNA itself is made up of adenine, thymine, guanine, and cytosine, then, these chemical compounds wrap around each other to form a double helix. These chromosomes contain around 20,500 genes and even with such a large number our variations are caused by less than 1% of our genes according to the Human Genomes Project in 2003. These variations also come from genotypes and phenotypes. A genotype is the complete set of genes that make a person’s hereditary, whereas, a phenotype are psychological, behavioral, and psychological features that result from the interaction between genes and the environment.

We all know that our genes are what give us our physical characteristics such as, eye color, hair color, the color of our skin, whether or not you’ll have freckles and how short you’ll be or how tall you’ll be. (pg91) Not only can our physical characteristics be determined from our genes but our behavior can be determined as well. Although it is more difficult to perform experiments on the human race, there has been some research that can prove whether genetics have any influence on the behavior of a human; to do so they performed research that would allow them to separate genetic and environmental influences. This research, kind of hits close to home for me because they did a study on twins,

Is behavior learned? It is inborn? What of aggression, intelligence, and madness? There is a crucial relationship between the behavior of humans toward their own kind and the view of life they hold. Interest in behavioral genetics depends on wanting to know why people differ. According to Jack R. Vale, in Genes, Environment, and Behavior, recognition of the importance of hereditary influence on behavior represents one of the most dramatic changes in the social and behavioral sciences during the past two decades. A shift began toward the more balanced contemporary view that recognizes genetic as well as environmental influences on behavior. Behavioral genetics lies in its theory and methods, which consider both genetic and

Human character and behaviour are not only shaped by the genes that encompass the individual’s genotype. Human character comprising mainly of personality, sexuality, morality and intelligence are the products of genetic determinism as well as external environmental factors. “Single genes can have surprisingly strong influences on particular aspects of behaviour.” (Frank., 2009)

According to McGue (1998), the nature of genetic and environmental influence on individual are differences in cognitive ability, personality and interest and

Some psychological models assert that a proportion of our personality is inborn and permanent (Hollander, 1971), that a psychological core at the center of our personality gives us enduring, inner characteristics. Hans Eysenck (1965) suggests that our motivation and emotion are related to biological differences in brain function and proposed that 75% of our personality is based on genetic influence and 25% on environmental influence. Research by Peter Whybrow (1999) on identical twins separated at birth examined how their different environments shaped their personalities. He found that around 40% of personality should be credited to genetics, with 60% determined by outside factors.