Good cop, bad cop, also informally called the Mutt and Jeff technique,[1] is a psychological tactic used in interrogation and negotiation, in which a team of two people take opposing approaches to the subject.[2] One interrogator adopts a hostile or accusatory demeanor, emphasizing threats of punishment, while the other adopts a more sympathetic demeanor, emphasizing reward, in order to convince the subject to cooperate.[3] It is an instance of the Reid technique.[4]