brendgen et al

Question 1

aim ?

Answer 1

• to find out if there is a difference between physical and social aggression in 6 year old school children by surveying teachers and class mates.
• in particular to see if PA children are also SA
• to see if the link is due to genetics or social situation by comparing MZ and DZ twins.

Question 2

what was the sample?

Answer 2

234 pairs of twins - from the Quebec Newborn twin study ( Longitudinal study )

Question 3

what type of study was used?

Answer 3

longitudinal and was on going but Brendgen used the data from the children were six years old,

Question 4

how many sets of MZ twins were there?

Answer 4

44 sets of males and 50 sets of females

Question 5

how many sets of DZ twins were there?

Answer 5

41 boys 32 girls and 67 mixed gender

Question 6

when did the kids enter the study ?

Answer 6

when they were born

Question 7

what method of gathering data was used?

Answer 7

questionnaires

Question 8

what were teachers asked to do?

Answer 8

rate each student on a 3-point scale (0= never, 1= sometimes 2 = often) based on statements such as:

• tries to make others dislike a child
• physically attacks others
• gets into fights

Question 9

what were the children asked to do?

Answer 9

they were given pictures of the classmates and had to circle three that best fit the descriptions:

• gets into fights
• spreads rumours

Question 10

what statistical test was carried out?

Answer 10

chi squared

Question 11

were teacher and peer ratings similar?

Answer 11

yes there was no significant difference - moderate correlation between agreement,

Question 12

where there any differences between teachers and peers ratings?

Answer 12

yes

• teachers rates boys more PA and girls more SA
• peers rated boys to be both more PA and SA.

Question 13

what results were found within the twins in terms of PA ?

Answer 13

MZ twins correlations for PA was twice as high compared to DZ twins
for example they got a teacher rating of 0.79 (high)

Question 14

what differences were found regarding social aggression?

Answer 14

MZ twins and DZ showed similar correlations

Question 15

what conclusions can be made about the results?

Answer 15

• that SA is more a cause of someones environment

- where as PA is more genetic.

Question 16

validity?

Answer 16

• high ecological validity as took place at school natural environment for children

Question 17

what makes the sample generalisable?

Answer 17

Brendgen uses a large sample (234 twin pairs), so unusual children (anomalies) with very high or low levels of aggression out to be “averaged out” by the size of the data. This makes the sample representative.

Question 18

what doesn’t make the sample generalisable?

Answer 18

• 88 sets of twins disapeared from the twin study at the 6 years old point - and if they added to making the sample more diverse than the sample may now be less generalisable.

Question 19

reliability?

Answer 19

• Brendgen uses established questionnaires to measure aggression. These can easily be replicated, making the study reliable.
• Two researchers visited each classroom, suggesting the study has inter-rater reliability.
• There was a strong correlation between teacher- and peer- ratings, suggesting the scores are reliable.

Question 20

application?

Answer 20

• If social aggression is strongly linked to environment, it must be possible to reduce the worst effects of verbal bullying, gossiping and “trolling” in social media by children, by using early intervention.
• Classes and workshops might help children learn less aggressive ways of interacting.