Displacement is another defense mechanism that can explain the propensity of many medical educators to bully students, and may operate subconsciously.[4] Displacement entails the redirection of an impulse (usually aggression) onto a powerless substitute target.[5] The target can be a person or an object that can serve as a symbolic substitute.[6] Displacement can operate in chain-reactions, wherein people unwittingly become at once victims and perpetrators of displacement.[7] For example, a resident physician may be undergoing stress with her patients or at home, but cannot express these feelings toward patients or toward her family members, so she channels these negative emotions toward vulnerable students in the form of intimidation, control or subjugation.[8] The student then acts brashly toward a patient, channeling reactive emotions which cannot be directed back to the resident physician onto more vulnerable subjects.[8]