Brendgen Contemporary Study

Question 1

What are twin studies?

Answer 1

• able to see trait/behaviour to compare between how similar they are
• uses concordance rate

Question 1

What is concordance rate?

Answer 1

• if a concorodance rate is 100% this means their trait/behaviour is highly due to genetics
• e.g. MZ would have a higher concordance rate

Question 2

What was the aim of Brendgen Study?

Answer 2

• investigate aggression in MZ and DZ twins
• discover the extent of social or physical aggression is explained by genetic and environemetnal

Question 3

What was the procedure in Bredgen?

Answer 3

• used teacher ratings by rating each child the social and physical agression
• used peer ratings where classmates rated their social and physical aggression
• they were given a booklet of photographs of all the children in their class

Question 4

How much genes does MZ and DZ share?

Answer 4

MZ are identical twins they share the same genes
DZ are nonidentical twins and share 50 percent of their genes

Question 5

What are the assumptions of twin study?

Answer 5

• assume that MZ and DZ share the same environment and the only difference between the groups are genetics

Question 6

What were the main important findings of Brendgen?

Answer 6

• highest teaching and peer rating for social aggression were 60% and 54% due to environment
• lowest teaching and peer rating for social aggression were 20% and 23% due to genetics
• highest teaching and peer rating for physical aggresion were 63% and 54% due to genetics
• lowest teaching and peer rating for phyiscal agression were 37% and 46% due to environment
• statistical test showed high physical agression **led to high social **aggression
• but wasn’t true that high social aggression led to high physical aggression

Question 7

What was the conclusion for Brendgens Twin Study of Agression?

Answer 7

• the data concluded that genetic characteristics predispose some children to aggressive behaviour
• ## genetics characteristics such as poor self-control, irrtitable temperment

Question 8

The sample was 322 but the sample went down by ____. How many sample were ?

Answer 8

The same consisted of 322 pair of twins but was reduced by 234 pairs of twins
- Twin studies usually have a large sample with many various data due to twin being investigated by companies by e.g. QNTS which contains longitudinal studies of twins from 5 months

Question 9

How were the twins assigned to catgeories of MZ and DZ

Question 10

What is shared environment and non-shared environment?

Answer 10

• shared environment is home
• non-shared environemnt is friends/school

Question 11

What comparisons were from peer and teaching ratings?

Answer 11

• there was a moderate correlation between peer and teaching ratings

Question 12

What experiment was brendgen?

Answer 12

• Brendgen twin study experiment was a natural experiment
• there were naturally IV occurings which were MZ and DZ twins
• there was no manipulation