Twin studies

Question 1

What are twin studies

Answer 1

• test nurture/ nature
• monozygotic twins share 100% same DNA
• Dizygotic share 50%

Question 2

How are similarities measured?

Answer 2

• Concordance rate

- if equally high or low the researcher may say there is no significant genetic component

Question 3

Brendgen: Aim

Answer 3

• see if social aggression is genetic or environmental

- see if social aggression shares same cause as physical

Question 4

Brendgen: Sample

Answer 4

• Quebec university
• born between november 1995 and july 1998
• 234 pairs tested
• 44 pairs MZ males, 50 MZ females , 41 DZ m, 32 DZ f, 67 DZ mixed

Question 5

Brendgen : Procedure

Answer 5

• collected longitudinally
• teacher rating - 3 point scale - questions - eg to what extent does the child get into fights
• peer rating - booklet of photos containing behaviour descriptions eg gets into fights

Question 6

Brendgen : Results

Answer 6

• higher correlation between ratings of MZ twins on physical aggression than between same sex DZ
• scores for social aggression similarly correlated meaning could be caused by environmental factors
• correlation between physical and social aggression due to genes

Question 7

Brendgen : Conclusion

Answer 7

• strong genetic component in physical aggression