The 'bad cop' takes an aggressive, negative stance towards the subject, making blatant accusations, derogatory comments, threats, and in general creating antipathy between the subject and himself. This sets the stage for the 'good cop' to act sympathetically: appearing supportive, understanding, in general showing sympathy for the subject. The good cop will also defend the subject from the bad cop. The subject may feel he can cooperate with the good cop out of trust or fear of the bad cop. He may then seek protection by and trust the good cop and provide the information the interrogators are seeking.
Although the technique is especially useful against subjects who are young, frightened, or naïve, it may still cause an instinctive psychological response in those who are familiar with it. However, as they are aware of the attempted manipulation, they may just close-down entirely or attempt to disrupt the procedure. Experienced interrogators assess the subject's level of intelligence and experience with the technique prior to its application.[citation needed]
There are various countermeasures available that can disrupt the tactic or cause it to backfire:[original research?]
- An experienced subject may choose to deliberately bait the 'bad cop' with provocative behavior of his own short of violent provocation (such as derogatory remarks about the bad cop or his family, racial, ethnic and gender slurs if applicable, offensive gestures), hoping that the 'bad cop' will lose self-control and react violently towards the subject. Most liberal democracies expect professionalism from law enforcement personnel, so any physical violence towards a subject during interrogation in the absence of bona fide physical provocation could compromise the prosecution's case or lead to civil or criminal legal consequences for the interrogators.[citation needed]
- Severe verbal abuse or otherwise insulting behavior targeted at the 'good cop' has also proven highly disruptive on occasion.[citation needed]
