Oct 22, 2013 ... Twin studies are a major source of information about genetic effects on behavior, but they depend on a controversial assumption known as the equal environments assumption. (EEA): that similarity in co-twins' environments is not predictive of similarity in co-twin outcomes. Although evidence has largely ...

greater degree of similarity in the rearing environments of MZ relative to DZ twins does not bias the results of twin studies. Behavior geneticists claim that the similarity in outcomes is largely unaffected by similarity in rearing environments for MZ and. DZ twins. This claim is known as the equal environments assumption (EEA) ...

Mar 27, 2016 ... Felson J. What can we learn from twin studies? A comprehensive evaluation of the equal environments assumption. Soc Sci Res. 2014;43:184–99. 5. Fosse R, Joseph J, Richardson K. A critical assessment of the equal-environment assumption of the twin method for schizo- phrenia. Front Psychiatry. 2015 ...

In May 2005, the American Political Science Review published an analysis of twins' political ideologies by Alford ... does not always hold in twin studies, potentially leading to inflated estimates of genetic influence. (e.g., see ... Hatemi 2009), it is essential for critiques of the equal environment assumption to demonstrate ...

twin studies: what can they tell us ... Twin studies used to be almost the only way to compare the influence of genes against the environment on personality and behavior .... First, the “equal envi- ronments” assumption states that the environments of iden- tical twins are no more similar than the environments of fraternal twins.

Jul 5, 2017 ... environments assumption in twin studies of personality traits. Behav Genet 1976; 6: 43–52. 41 Felson J: What can we learn from twin studies? A comprehensive evaluation of the equal environments assumption. Soc Sci Res 2014; 43: 184– 199. 42 Tropf FC, Stulp G, Barban N et al: Human fertility, molecular ...

It is argued that the main theoretical assumption of the twin method—known as the “equal environment assumption”—is not tenable. The twin method is therefore of doubtful value as an indicator of genetic influences. Studies of reared -apart twins are discussed, and it is noted that these studies are also vulnerable to ...

Developmental Review 20, 539–567 (2000) doi:10.1006/drev.2000.0511, available ... is placed on twin and adoption studies. ADHD twin studies depend on the validity of the equal environment assumption .... We have already noted that no family inheritance study can control for environment in human research; such data, ...

This is the equal environment assumption (EEA). With c. 2 assumed equal regardless of zygosity, the term h. 2 can be expressed as. ) (. DZ. MZ r r h. −. = 2. 2. With a numerical value on h. 2 inserted in [1], c. 2 can be derived as. 2. 2 h. rcMZ −. = This is the simplest form of the twin model. Although studies often diverge from ...

we show that the most crucial of these, namely the equal environments assumption (EEA), may not hold. Consequently ... Together, these problems can readily account for the classical patterns of twin correlations ... review, Joseph ( 2000) cites questionnaire studies revealing very large differences between MZ and. DZ pairs ...

We use a longitudinal study of twins collected through- out childhood to reveal the developmental pattern of political attitudes. Our focus is on the transmission of ... interest (commonly called the ''equal environments assumption). The concern is that twin studies would overestimate genetic influences if this assumption is.

attitudes, but we conclude with a discussion of the way in which the incorporation of biology can enhance research in virtually .... This will be the first time political scientists have unfettered access to twin studies and the first time a twin study asks .... This crucial equal environments assumption (EEA) is open to challenge.

The author concludes that the study failed to support the equal environment assumption, and that genetic interpretations of twin method data in political science and the behavioral science fields should be rejected outright. Keywords: behavioral genetics, equal environment assumption, political science, twin study.

Mar 16, 2017 ... Twin study. Media behavior. DeFries-Fulker regression. a b s t r a c t. A behavior genetics perspective suggests both social and biological forces ... biological nature and the nurture we receive from the world around ..... 6 ACE modeling, it should be noted, relies the “equal environments assumption”. (EEA).

The equal environment assumption for psychiatric twin studies has been more rigorously examined and continues to receive empirical support. Twin studies are beginning to examine genotypeenvironment interaction in the etiology of psychopathologic conditions and to address the nature of putative environmental risk ...

could be completely altered in the future by a simple environmental change” ( 1974: 400). To illustrate this point in relation to the twin studies let us first take a simple example of two pairs of plant seeds. The one pair is genetically identical, and the other pair is only fifty percent alike. No matter which (equal) environment we ...

been tested with a male population of 24 monozygotic (MZ) twins, 10 dizygotic ( DZ) twins, 8 non-twin siblings and 12 unrelated .... portant assumption be made: the equal environment ... 1 From the EEA we can draw that the excess of similarity (for an investigated parameter) exhibited by MZ twins that is not present in DZ.

Mar 27, 2016 ... In our study we asked: 'Why do brighter people tend to live longer?' To test this empirical question, we turned to three samples of twin data. All data have limitations. We devoted ... measures of genes or environments, the power of pedigree- ... assert that the equal environmental similarity assumption.

Jul 12, 2016 ... Fertility and sterility, 83(5),. 1422-1428. http://dx.doi.org/10.1016/j.fertnstert. 2004.11.053. Felson, J. (2014). What can we learn from twin studies? A comprehensive evaluation of the equal environments assumption. Social Science Research, 43, 184-199. http://dx.doi.org/10.1016/j.ssresearch.2013.10. 004.

Mar 5, 2016 ... REVIEW. The Prenatal Environment in Twin Studies: A Review on Chorionicity. Kristine Marceau1,3,7. • Minni T. B. McMaster5. • Taylor F. Smith1,4. •. Joost G. ... we review and summarize studies which have examined the influence of .... the equal environments assumption, which could also bias heritability ...