Most commonly these methods are used in unison good cop/bad cop, the good cop pretends to save the suspect from the bad cop saying things like just tell him what he wants before it gets worse. The suspect will hopefully find comfort from being saved and confess sometimes confessing to even more than he/she was questioned about.
Although these interrogation methods seemed a little like trickery it still is far better than tactics once used such as torture of suspects to make them confess. These methods include psychological as well as physical torture. Some of the psychological methods included blackmailing, exploitation of phobias; e.g., mock execution, leaving suspects in a room full of spiders, interrogations that lasted for an unreasonable