School bullies are also likely to bully their brothers and sisters at home, according to an Italian study that included 195 children between the ages of 10 and 12.
The participants -- all with a sibling no more than four years older or younger than them -- were asked whether they bullied or were bullied at school or at home. The findings were published online Nov. 30 in the British Journal of Developmental Psychology.
"We found that children with older male siblings were the most victimized group," study author Ersilia Menesini said in a news release from the British Psychological Society. "It was also the case that significantly more boys than girls told us that they bullied their sibling -- who was most likely to be younger than them. It's likely that this form of sibling bullying is all about maintaining a position of dominance."
But for girls, "bullying is mainly related to a poor quality of sibling relationship and not to birth order. In fact, high levels of conflict and low levels of empathy were significantly related to sibling bullying and sibling victimization," Menesini said.
The researchers also found a significant association between bullying and victimization at school and home. Children who bullied siblings were likely to bully schoolmates, while children bullied at home were likely to be bullied at school.
"It is not possible to tell from our study which behavior comes first, but it is likely that if children behave in a certain way at home, bullying a sibling for instance, if this behavior goes unchecked they may take this behavior into school," Menesini said.