A recent study suggests they can. Researchers from Virginia Commonwealth University, in Richmond, and the University of Illinois system studied more than 5,500 students at 37 middle schools, focusing on this age group because aggressive behavior tends to escalate during the transition from childhood to adolescence. The researchers found that violent behavior in general increased throughout the three years of middle school, especially among girls. The good news is that children whose parents actively advocate peaceful conflict resolution acted less aggressively, even if they attended more violent schools.