Origins of Bullying Eley et al. (1999) Is antisocial behaviour genetic? 1500 pairs of British and Swedish twins were studied. Findings: Identical (MZ) twins showed a higher correlation of aggressive antisocial behaviour than fraternal (DZ) twins. Leiu & Raine (2004) Does malnutrition lead to violence? A 14 year study of 1000 children living on the island of Mauritius. At age 3, researchers selected children suffering from malnutrition. A control group who did not suffer from malnutrition were also studied. At age 8, 11, and 17 researchers investigated how the children were behaving in school and at home based on either teacher or parent evaluations. Findings: Children suffering from malnutrition showed an increase in aggressive behaviour (e.g. 51% increase in violent behaviour by the age of 17). Dodge (1980) How do bullies think? Design: Aggressive and non-aggressive boys were given a hypothetical story to read. Each boy imagined that a classmate spilled a lunch tray all over his back. The boys were then asked about the classmate’s intentions and how they would respond if this really happened to them. Findings: The aggressive boys read hostile intent into the story 50% more frequently than the others and responded more aggressively. Negative attributions led to negative attitudes. Eron (1987) Parenting and violence Findings: Parents of bullies were found to be often authoritarian-using very strict and often physical methods of punishment. Totten (2003) Parenting and Girlfriend abuse 30 abusive adolescent males from a large city in Canada were studied with semi-structured interviews. Mean age of the boys was 15.6 years, 6 belonged to an ethnic minority , and the rest were white. Many were gang members and most had dropped out of school early. Findings: the boys had all been exposed to violent behaviour in the family. The fathers all used violence to control family members or to defend their honor. In some cases, the fathers had given them instructions on how to abuse women in particular situations.