Are twin studies case studies?

Though all twins, through their similarities and differences, offer insight into the effects of genetics and the environment, twins who were reared apart offer particularly powerful case studies.

What is wrong with twin studies?

Although the authors of psychiatry and psychology textbooks and other mainstream publications usually endorse genetic interpretations of psychiatric twin studies uncritically, there is a fatal flaw underlying these studies: identical twin pairs grow up experiencing much more similar environments than experienced by …

What are twin studies used for?

We study twins to understand how much of the difference in a trait between people is caused by genes and how much is caused by the environment. These studies are important because they help scientists quantify genetic and modifiable environmental factors that increase the risk of certain diseases.

What have twin studies revealed?

Through studying twin pairs we identified the first gene that influences both mammographic density (the amount of white areas on a mammogram) and risk of breast cancer, called LSP1. His team found monozygotic (identical) twins were highly similar for mammographic density, which predicts future risk of breast cancer.

How many people are involved in twin studies?

Funded by the National Institutes of Health, the 21 center, 10-year study has enrolled nearly 12,000 children ages nine to 10, including roughly 1,000 twin pairs. Such a large study offers new opportunities in neuroscience research. “Ten years ago, it was common to report findings on only 10 people,” says Iacono.

When was the first study of twins separated at birth?

Such broad-ranging genetic effects first came to light in a landmark study — Minnesota Twin Family Study — conducted from 1979 to 1999, which followed identical and fraternal twins who were separated at an early age.

Can a twin study be used to study intelligence?

So, researchers who use twins to study intelligence might have to worry more about nonrandom mating than researchers who study personality. Twin study designs and statistical analysis methods are also constantly evolving and improving.

How are twin studies used to determine heritability?

Twin and kinship studies are used to determine heritability – the extent to which variations in behaviour can be attributed to genetic factors. e.g. 50% heritability for IQ means that differences in IQ are half (50%) due to genetics, and the other half is environment.