brendgen

• What type of aggression was tested in Brenton's study?

  Social and physical aggression
• What type of study was Brenton's research?

  Twin study
• Where was Brenton's study conducted?

  Quebec, Canada
• What was the sample size of twin pairs in Brenton's study?

  322 pairs
• What years did the sample of twin pairs come from?

  1995 to 1998
• How many pairs of twins had complete data gathered?

  234 pairs
• What methods were used to determine if twins were monozygotic or dizygotic?

  Physical resemblance questionnaires and DNA tests
• How many DNA tests were conducted in the study?

  123 tests
• What percentage of the DNA tests were correct?

  94%
• How long was the longitudinal aspect of Brenton's study?

  6 years
• How many classrooms were looked into during the study?

  409 classrooms
• What type of consent was gathered for the study?

  Written consent from parents
• What were teachers asked to rate in children?

  Aggression
• How many questionnaires did teachers complete?

  Six questionnaires
• What did teachers have to mark on the questionnaires?

  Their level of agreement
• What standardized scale was used for marking agreement?

  Zero to two scale
• What does a score of zero represent on the scale?

  Never
• What does a score of one represent on the scale?

  Sometimes
• What does a score of two represent on the scale?

  Often
• In what languages were the instruments available?

  English and French
• Who verified the instruments used in the study?

  Bilingual judges
• What type of aggression was measured by statements like "tries to make the others dislike a child"?

  Social aggression
• What type of aggression was measured by statements like "gets into fights"?

  Physical aggression
• What scores did each twin receive from their teacher?

  A physical and social aggression score
• What was the next stage after teacher ratings?

  Peer ratings
• What did children receive to assist in peer ratings?

  Photographs of their classmates
• Who ensured that children recognized the photographs?

  Two researchers
• What were children asked to do with the photographs?

  Circle pictures of three children
• What descriptors were used to measure social aggression?

  Tells others not to play with a child
• What descriptors were used to measure physical aggression?

  Gets into fights, bites, kicks
• What percentage of physical aggression in six-year-olds is linked to genes?

  50 to 60%
• What percentage of social aggression can be linked to genes?

  20%
• What limitation was noted about the study's sample size?

  Not big enough to establish differences
• What was not established regarding aggression in the study?

  Different genetic/environmental contributions
• What two types of aggression were measured in the study?

  Social and physical aggression
• Generalisability.

  Strength

  Reasonably large sample of male and female twins

  Roughly equal numbers of males and female so no gender bias

  Not unusual in respect to education income age parents at birth, marital status
• Generalisability

  Weakness

  Limited age range of five months to 6 years aggression and other range ranges may have a different explanation

  Twins may not be typical of all siblings

  Western culture may not be generalised to children outside of Canada e.g. in warrior cultures
• Validity

  strengths

  The rating scales were standardised. The same questions asked to all teachers in the same questions for peers

  weakness

  because the rating scales needed to be translated into French for some teachers/classmates is possible that some items may not have been interpreted in the same way by everyone
• Strengths in validity

  Both parent and teacher ratings of aggression reduces the chance of bias in scores not just one person deciding on one aggression score

  It was a longitudel enough study allows researchers to observe changes in individuals over time. Children who were initially were more physically aggressive. We're more likely to develop to be more socially aggressive.
• Weaknesses in validity

  • The assumption that high concordance rates regression for Monic twins must be a consequence of shared genes may not be correct. The high concordance rates could've been due to the shared environment.
  • Identification of some monozygotic twins based on physical appearance and questionnaires not DNA testing brackets only 123 were done therefore it may not be valid