Twin studies

Question 1

What do the studies support?

Answer 1

That there is a heritable trait that may increase the risk for criminal behaviour

Question 2

What was the earliest testing?

Answer 2

Johannes Lange (1929) a nazi psychologist with an unusual fascination for twins

Question 3

What were the findings from the earliest testing?

Answer 3

Monozygotic twins had a higher rate of concordance
10/13 MZ twins both served prison time
2/17 Dizygotic pairs of twins both served prison time

Question 4

Christiansen sample

Answer 4

3586 Pairs of twins

Question 5

Christiansen finidngs

Answer 5

Male twins:
MZ twins: 35%
DZ twins: 13%

Female twins:
MZ twins: 21%
DZ twins: 8%

Question 6

Strengths

Answer 6

Twins are a naturally occurring variable
Christensen supports a genetic view of criminality
Twin studies aided in the prevention of disorders

Question 7

Weaknesses

Answer 7

Lange’s study was poorly controlled and therefore lacked validity
the small sample size langue used isn’t representative of the general population
if the twins are brought up together their behaviour may be a project of their environment