Twin studies

Question 1

What is theory based on?

Answer 1

The belief that a heritable trait increases risk of crime

Question 1

Is it genetic or physiological?

Answer 1

Genetic

Question 2

What are MZ twins?

Answer 2

Identical, monozygotic

Question 3

What are DZ twins?

Answer 3

Fraternal, dizygotic

Question 4

What should happen if 1 MZ twin commits crime?

Answer 4

The other should also commit crime

Question 5

Which twins should be more similar and why?

Answer 5

MZ as their genes are 100% the same

Question 6

What is the concordance rate?

Answer 6

It shows the similarity of the twins.
Whether they act the same or have the same trait

Question 7

What are the strengths of this theory?

Answer 7

It was a natural experiment ( twins have a natural relationship) so the results are stronger and more valid
Christiansen used over 3,500 twins pairs ( good sample)
MZ twins did act more similar ( 35% and 21%)

Question 8

What are the weaknesses of this theory?

Answer 8

If twins are brought up in the same environment, environment is just as likely to be the cause.
If genes were the only cause, MZ twins would have 100% concordance
Lange had a small sample ( 30 twin pairs)