Minnesota Twin Studies

Table 3-1 examines the correlations between selected characteristics for the identical twins separated at birth and the twins raised together. When compared to each other, they both have very similar brain wave activity, blood pressure and heart rate in the physiological characteristics. The Raven intelligence test was very similar, but the WAIS IQ displayed a bit of difference when compared to the other comparisons made. Personality wise, they typically had similar personalities at the same rate as twins raised together. Psychological interests were off a little bit, but still very similar. The twins that were separated at birth had less similar psychological interests compared to the twins

In this study, they are used several type of method, one of the technique is used two or more test instrument to ensure the adequate coverage, for example the participants were given a battery of personality and mental ability tests, interest and value inventories and psychomotor tests. In addition, separate of examiners administer the IQ test, life history interview, psychiatric interview and sexual life history interview. The twin also complete questionnaire independently under the constant supervision of the staff members. Twin studies are valuable to researchers because identical twins share 100% of their genes and fraternal twins share, on average, 50% of their genes. Both identical and fraternal twins share certain aspects of their environment (e.g. religious practices in the home). This allows researchers to estimate the heritability of certain traits. Participants are asked about academic ability, personality, and interests; family and social relationships; mental and physical health; physiological measurements. Of interest to researchers are prevalence of psychopathology, substance

Parallel to this, the focus on genetics is Particularly convicted in twin studies, which establish a comparison between monozygotic twins that are identical and dizygotic twins, which are opposingly non-identical. This distinction can be identified in Torgersens study, which compared MZ and same sex DZ twins where one proband had an anxiety disorder, and it was discovered that such disorders were 5x more frequent in MZ twin pairs, who mutually shared identical genetics.

Twin studies are a mainstay of the nature verse nurture debate because they allow researchers to conduct “natural experiments” on human beings. When researchers try to determine the relative importance of genetics and environment with regard to a certain condition, they have a hard time because they cannot generally get people with the same genes. This is where twin studies come in. Twins studies are part of the method used in behaviour genetics, which includes all data that are genetically informative. E.g. siblings, adoptees, pedigree data etc. Researchers use this method to estimate the heritability of traits and to quantify the effect of a person 's shared environment (family) and unique environment (the individual events that shape a life) on a trait.

The Minnesota Twin Registry started in 1983 and its goal was to establish a registry of all twins born in Minnesota from 1936 to 1955 to be used for psychological research.., T.J. Bouchard, working in conjunction with the University of Minnesota, started exploring the similarities and differences in characteristics like personality, career interests, and a variety of personal interests between identical twins who were reared apart. Research was conducted on twins from all over the world. The Minnesota Twin study gave scientists a new insight of the role of nature vs. nurture on human development and personality; it was the hope that twin studies would be able to tie genes to specific behaviors. From the study, we understand that twins who were separated at birth and raised in different families

Methods: The researchers needed a way to study a person who developed in a certain environment and how similar or different that person would be having been raised in a different environment. They came up with an experiment using monozygotic (identical) twins. Half of the pairs of twins were reared together (MZT); the other half were reared apart (MZA) and separated early in life. Each twin was individually given numerous surveys and

First we will look into the biological aspect of human behavior. Biological pertains to one’s body chemistry and from a psychological standpoint the chemistry of the brain. No two people have exactly the

Both family and twin studies face the problem of ignoring environmental impacts. In family studies, genetically similar members of the same family tend to spend more time together, therefore

(P1)The biological approach means that our behavior is the cause of biological factors. This approach looks at our genetics to construct a reason why we act the way we do and why we develop abnormal behaviors. The brain and nervous system are the biological approach and so are chemical changes in the body .This can mean chemical reactions in the brain. For instance, in eating disorders - twin studies were carried out and it was shown that if one identical twin suffered from an eating disorder then the other twin would also be more likely to suffer from a disorder as well. This did not happen with non-identical twins, suggesting that the

In the summary and selected experts from “Sources of Human Psychological Differences: The Minnesota Study of Twins Reared Apart” (Bouchard, Lykken, McGue, Segal and Tellegen) there were various research methods used in the study. The study focused on whether nature or nurture had an affect on twins behavior. To start, I believe this study was a cross-selection research where analyzation takes place at a single point in time rather than longitudinal research where research is collected over time.The reason for this is because it would be extremely difficult and time consuming to keep a close eye on over 200 children throughout their lifetime. This would also cause in affect if the study method would have been just plain observation

Bouchard and Lykken’s study has been criticized for many things. For one, other psychologists believe that the information published is not complete, and therefore their findings are not reliable. Another criticism is that Bouchard and Lykken do not consider many environmental factors that the twins experienced growing up, creating unreliable and biased research. The biggest issue people have with this study is the assumption Bouchard and Lykken made when they determine that the twins who grew up together had identical home environments. That the twins were not treated differently by their parents or their environment; that they had the same exact experiences growing up. This, the

The study to aid the relationship between genetic influence and conduct is the Minnesota Twins study, which meant to watch the impact of environment and genetic influence upon a large number of variables which included: brainpower remainder, identity and word related/professional perks, by exploring the connection between these elements in twins raised separated utilizing MZTs as a control. Regardless of these shortcomings the study does demonstrate a solid connection between genetic influence and insight, proposing that genetic influence has a generous impact on conduct. Heston, in 1966, led an examination to test to what degree schizophrenia is because of hereditary works. The outcomes demonstrated that 10% of the grown-ups with schizophrenic moms were diagnosed with schizophrenia, while

The second explanation is genetics. Research done on twin studies found that identical twins that were raised apart were more statistically similar to each other. A meta-analysis was done that concluded that forty percent of variance in personality can be attributed to genetics. The third explanation of

Biological Level of Analysis (BLOA) deals with biological adaptations at a biological level. BLOA states that cognitions, emotions and behaviours have a physiological basis to all of them. There are 3 main principles that revolve and outline the BLOA. Foremost, Behaviour is innate, as it is genetically based, so it rational to conclude that behaviour is genetically influenced by evolution. Secondly, Animal research may inform our understanding of human behaviour, as to why a lot of research is done on animals. Lastly, Cognitions, emotions and behaviours are products of than anatomy and physiology of our nervous and endocrine

From these studies, researchers have found that twins who have grown up in the same household share similarities in the way they think, act, dress, speak, etcetera. However, with the first type of twin studies, researchers could not differentiate whether the similarities were due to them having identical/similar genetic makeups or growing up in the same environments. Therefore, in order for psychologists to know whether similarities in twins are genetic or socially influenced, they studied twins who grew up in completely different households and environments. The study showed that despite growing up with a different family and in a different environment, they still had noticeable similarities in fashion, interests, and thought processes (K.W. Brown, personal communication, August 29, 2017). Twin studies, as well as other studies, have greatly contributed to our understanding of overall role that genes play in the development of psychological traits and behavior.