Twin Studies

Question 1

What is the primary purpose of twin studies?

Answer 1

The primary purpose of twin studies is finding out whether a behaviour or disorder has a genetic component

Question 2

What statistic do twin studies use in order to determine whether a behaviour or disorder has a genetic component?

Answer 2

Twin studies use the concordance rate of twins with respect to the disorder being considered - this is the probability of one twin having the disorder if the other already has it, expressed as a percentage

Question 3

How are MZ (identical) and DZ (non-identical) twins used in order to determine whether a condition is due to a genetic or environmental component?

Answer 3

MZ twins have a shared environment and share 100% of their genetics, meaning that any differences (low concordance rate) will be due to a non-shared environmental factor. DZ twins have a shared environment but share only 50% of their genetics, meaning that differences (low concordance rates) may be caused by genetics or non-shared environment - comparison to MZ twins will identify which

Question 4

+ Evidence for nature/nurture

Answer 4

Twin studies provide evidence for which behaviours are nature/nurture, which gives the findings significant practical application, e.g. interventions and therapies

Question 5

+ Objective

Answer 5

Twin studies are objective in their measure of concordance rates, and are therefore scientific

Question 6

• Twins hard to find

Answer 6

Twins with the behaviours f interest are hard to find, leading to small sample sizes and thus results that are hard to generalise

Question 7

• Categorisation on appearance

Answer 7

Categorisation of MZ and DZ twins is done on appearance, which can lead to inaccurate results