Brendgen et al (2005) A01 Flashcards
What was the aim of the study?
To investigate aggression in MZ and DZ twins to discover:
The extent to which social and physical aggression are explained by genetic and environmental influences.
What kind of study was this?
Correlation
How many pairs of twins were there?
234
Where did they recruit the twins from?
Quebec Newborn Twin Study
How old were the twins when they were recruited for Brendgen’s study?
72 months (6 years)
Who did Brendgen gather information from about the social and physical aggression of each child?
Teachers and Peers
How were the teacher’s opinions of each child rated?
Using a 3 point likert scale (never, sometimes, often).
Give an example of social aggression which was on the teacher questionnaire.
‘Says bad things’
Give an example of physical aggression which was on the teacher questionnaire.
‘Hits others’
How did the researchers get information from the peers?
They were given a booklet of photos of all children in their class and they had to choose three children on each page who best matched a description of their behaviour.
What were the two descriptions for social aggression given to the peers.
‘Tells others not to play with a child’
‘Tells mean secrets about another child’
What were the two descriptions for physical aggression given to the peers.
‘Gets into fights’
‘Hits, bites or Kicks others’
What are the main findings with regards to social aggression?
20% (teacher ratings) to 23% (peer ratings) of social aggression explained by genetic factors.
Social aggression was mostly explained by non-shared environmental factors.
What was the main finding with regards to physical aggression?
Physical aggression was mostly explained by genetic factors and partly by non-shared environmental influences.
What is a conclusion of the study?
Genetic characteristics predispose some children to aggressive behaviour in general (poor self-control, irritaable, temperament).
