- 1 What are twin and adoption studies?
- 2 What are the problems with twin studies?
- 3 Why do behavior geneticists use twin and adoption studies?
- 4 What have twin studies shown?
- 5 How do twin studies explain crime?
- 6 How do twin studies and adoption studies differ?
- 7 What are the limits of twin studies?
- 8 Why are twin studies unethical?
- 9 Why are twin studies unreliable?
- 10 How does genetics and environment influence the similarities and differences within twins?
- 11 What are two problems with adoption studies of genetic influence?
- 12 How do twin studies allow us to separate nature from nurture?
- 13 Why is twin studies important?
- 14 Who carries the twin gene?
- 15 What is concordance rates in twins?
What are twin and adoption studies?
Twin and adoption studies allow one to tease apart the effects of genes and environments. Twin studies compare the patterns of behavioral characteristics between identical, or monozygotic (MZ), and fraternal, or dizygotic (DZ), twins.
What are the problems with twin studies?
The most common objections to twin studies have been: (1) Twins have almost always been reared to- gether and this common rearing may have con- tributed to increased concordance in monozygotic (MZ) twins because of psychological characteris- tics unique to such pairs (8, 29);
Why do behavior geneticists use twin and adoption studies?
Behavioral geneticists study how individual differences arise, in the present, through the interaction of genes and the environment. When studying human behavior, behavioral geneticists often employ twin and adoption studies to research questions of interest.
What have twin studies shown?
Modern twin studies have concluded that almost all traits are in part influenced by genetic differences, with some characteristics showing a stronger influence (e.g. height), others an intermediate level (e.g. personality traits) and some more complex heritabilities, with evidence for different genes affecting
How do twin studies explain crime?
Twin studies. Twin studies support the contention that a heritable trait may increase risk for criminal behavior.
How do twin studies and adoption studies differ?
In general, twin studies investigate the role of nature (genes) and adoption studies investigate the role of nurture (upbringing). Adoption studies and twin studies are always natural experiments.
What are the limits of twin studies?
Limitations of twin studies Results from twin studies cannot be directly generalized to the general population, due to lack of randomization; in addition, they are different with regard to their developmental environment, as two fetuses growing simultaneously.
Why are twin studies unethical?
The study, which has since been criticized for being unethical — for example, neither the children’s biological parents nor the adopting families were informed — was an attempt to get at the central psychological questions of “nature versus nurture” and the “twinning reaction.”
Why are twin studies unreliable?
Twin studies make the unjustified assumption that twins share the same prenatal environment. Thus, one cannot conclude that if identical twins are more similar in some behavior than fraternal twins, the increased similarity must be caused by the genes they share.
How does genetics and environment influence the similarities and differences within twins?
Any differences between identical twins is expected to be due to environmental factors since they are genetically identical, whereas fraternal twins only share half of their genes on average. When a genetic influence is dominant, the identical twins would have more trait similarity than fraternal twins.
What are two problems with adoption studies of genetic influence?
Adoption studies have pinpointed that some traits are linked to genetics, for example, Schizophrenia, IQ and criminality, however other compound factors (such as age and environment) can have an impact too.
How do twin studies allow us to separate nature from nurture?
The traditional way of studying nature versus nurture relies on twins. Because identical twins share the same genetic code, comparing the health of twins can help determine whether genetic or environmental factors play more of a role in their health.
Why is twin studies important?
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.
Who carries the twin gene?
While men can carry the gene and pass it on to their daughters, a family history of twins doesn’t make them any more likely to have twins themselves. 3 But, if a father passes on the “twin gene” to his daughter, then she may have a higher chance than normal of having fraternal twins.
What is concordance rates in twins?
Concordance, as used in genetics, usually means the presence of the same trait in both members of a pair of twins. Discordant rates that are higher than concordant rates express the influence of the environment on twin traits.