3.3.2 Contemp- Brengden et al (2005)

Question 1

3 Aims?

Answer 1

1) To investigate whether social aggression could be caused by genes or the environment and whether social aggression shared the same cause as physical aggression
2) To investigate whether a correlation between physical and social aggression is due to genetics or social situation
3) To investigate whether one type of aggression leads to another

Question 2

Sample?

Answer 2

• 234 twin pairs from Quebec Newborn Twin Study (QNTS)
  -Age 6
• 94 MZ twins
  -140 DZ twins of varying gender combos
  > 44p m MZ
  50P f MZ
  41p m DZ
  32p f DZ
  67p m/f DZ

Question 3

Method/design?

Answer 3

Longitudinal study at 5, 18, 30, 48, and 60 months and then again at 6 years.

Question 4

Procedure (teacher ratings)?

Answer 4

• 3-point Likert scale

-Agreeing on 6 statements taken from two pre-existing scales (such as the Direct and Indirect Aggression Scales)

-Statements incl “tries to make others dislike a child” for social and “gets into fights” for physical

Question 5

Procedure (student ratings)?

Answer 5

• Each child was given a book of photos of people in their class

-Then asked to circle three pictures of children they thought matched the 4 different behaviour descriptors

-The 4 descriptors included things like: “tells means secrets about another child” for social and “hits and kicks” for physical

Question 6

What were the results of Brendgen’s study for AIM1?

Answer 6

• There was a much higher correlation between the ratings of MZ twins on physical aggression than between same sex DZ twins

-Scores for social aggression were roughly equally correlated in MZ and DZ twins

Question 7

What can we conclude from the results of AIM1?

Answer 7

That physical aggression may be a result of genes and that social aggression may be the result of environmental factors.

Question 8

What were the results of Brendgen’s study for AIM2?

Answer 8

A correlation was found between physical and social aggression in the children that was best explained by genes.

Question 9

What can we conclude from the results of AIM2?

Answer 9

That aggressive tendencies in general are down to genetic factors but the expression of these tendencies is down to the environment.

Question 10

What were the results of Brendgen’s study for AIM3?

Answer 10

The data suggested that physical aggression may lead to social aggression but not the other way round.

Question 11

What can we conclude from the results of AIM3?

Answer 11

That the expression of physical aggression when young changes as children develop more ‘socially acceptable’ ways to show aggression. As their cognition develop, so do their abilities to demonstrate aggressive behaviour in new ways.

Question 12

Overall conclusions?

Answer 12

• There is a genetic component to physical aggression but not social aggression, which is more likely to be due to environmental factors.
• Children who were physically aggressive were also more likely to display social aggression
• As children grow they tend to become more socially aggressive because of social conventions

Question 13

GRAVE-Generalisability

Answer 13

P-High
E-Brendgen used a large sample of 234 twin pairs, across MZ and DZ twins such as 44 pairs male MZ, 32 pairs fem DZ
E-S, so anomalies such as children with unusually high or low levels of aggression would be averaged out, makes the sample more representative to be applied to a larger sample population.

P-Low
E- 88 twin pairs disappeared from the Quebec Newborn Twin Study (QNTS) before the 6 year/ 72 month testing mark, known as sample attrition.
E-W, If these missing twin pairs came from more disturbed or chaotic backgrounds in comparison to the rest of the sample, then the study presents a weakness whereby the study becomes less generalisable as the participants that may have represent a more niche part of the population that also share abnormalities such as disturbed home lives, are now lost from the study.

Question 14

GRAVE-Reliability

Answer 14

P - High
E - Gathered quantitative data from the teacher and peer ratings using a closed-answer questionnaire and a photo book
E - This therefore means they can be objectively compared easily if replicated
P - High inter-rater
E - Two researchers visited each classroom to explain the procedure to the peers who would be rating via circling photos
E - This suggests high inter-rater reliabilty that would ensure consistency of findings for genetics and aggression

Question 15

GRAVE-Application

Answer 15

If friends and family are significant influences on social aggression, this suggests that educating parents with better ways of handling their children and being beter role models might prevent children from being socially aggressive with their own friends.
Moreover, if social aggression is linked to the environment, it may be possible to reduce the worse effects of social aggression such as verbal bullying, gossiping and ‘trolling’ on social media. Classes may help children to learn healthier and less aggressive ways on interacting

Question 16

GRAVE-Validity

Answer 16

P - High
E - Ratings of twins by peers and teachers were done in the spring term
E - This suggests that results would be more credible due to being more familiar with the twins so assessment on behaviour more valid
P - High
E - The approach is not reductionist providing both biological and environmental reasons for aggression
E - This therefore gives more detail and a more holistic view on aggression in children as a whole to explain the complex phenomenon more in-depth

P - Low
E - There is limited control over the EVs, for example the relationship between peers prior to the data being recorded
E - Therefore researchers cannot be certain that there may or may not be favourable bias in who the classmates chose for negative behaviours
P - Low
E - Gathered correlational data from the natural experiment of concordance rates MZ and DZ twins on aggressive behaviour
E - Cannot establish cause and effect as never 100% also there may be bias created from assuming one twin will show the same behaviour as the other

Question 17

GRAVE-Ethics

Answer 17

P - Good
E - 88 ppts left the study at age 6
E - Showing that the right to withdraw wasn’t compromised by the pressures of staying in a longitudinal study

P - Bad
E - Children were asked to rate their peers with negative labels by circling photos of those matching 4 descriptors
E - They may cause psychological distress as the bad things could have harmful impact on friendship