Twin studies Flashcards
What is an MZ twin?
Identical twin, share 100% DNA
What is a DZ twin?
Non-identical twin, share 50% DNA
What does a twin study allow us to investigate?
Whether the cause of a behaviour or trait is nature (genetic) or nurture (environmental)
What is concordance?
The extent to which both twins share the same characteristic e.g. if twin 1 has Schizophrenia, what percentage of the time does twin 2 also have Schizophrenia
How is a twin study carried out?
Find a set of twins where at least one of them has the specific trait or characteristic being studied
Use a variety of strategies to ensure the allocation to MZ or DZ is accurate (e.g., DNA testing).
Measure the concordance rate in the other twin (how often the second twin also has the trait)
What is a strength of twin studies in terms of usefulness?
They help us determine whether a behaviour is due to nature or nature - useful in helping us determining why a behaviour may occur.
What is a strength of twin studies in terms of validity?
Can use DNA testing to determine if the twin is MZ or DZ
Often use triangulation of data to measure a specific trait
What is a weakness of twin studies in terms of generalisability?
Twins are relatively rare in the population. This is a weakness as the results from the twins may not be generalisable to the wider population.
What is a weakness of twin studies in terms of validity?
It is often assumed that the difference between MZ and DZ twins is the amount of DNA, but MZ twins are often treated more similarly than DZ - differences may be environmental not genetic
What is an example of a twin study in Psychology?
Brendgen
