· Suspects who are in custody are psychologically vulnerable. Many suspects are intimidated by jail conditions, and talk in order to please the jailers who are suddenly in control of their lives.

　　· Police often lead a suspect to believe that a confession or cooperation in naming other suspects will result in leniency. Although courts generally consider this to be improper police conduct （see, e.g., People v. Vasila, 45 Cal. Rptr.2d 355 （1995））, the police will usually deny that they promised leniency, and the judge will usually believe them.

　　· Police use the "good cop–bad cop" routine. In this ploy, one police officer is aggressive and overbearing toward a suspect. A second officer is helpful and courteous. Suspects perceive the second officer as "being on their side," and gratefully and voluntarily talk to the second officer.

　　· Many suspects talk voluntarily in the belief that anything short of a full written confession isn't admissible in evidence. They are mistaken. Anything they say to the police, even if at the time it seems to be in their favor, is admissible in evidence.

　　· Police may make suspects feel that their situations are already hopeless. For example, police officers may tell a suspect that the suspect failed a lie detector test, that a co-defendant confessed and incriminated the suspect or that the police have a videotape of the suspect committing the crime. Even if the police have lied, the resulting confession is usually admissible in evidence.

　　· Taking advantage of a suspect's guilt feelings, police officers may emphasize the harm that the suspect has caused to the victim, and stress that the suspect can begin to repay the victim by owning up to the misdeed. A resulting confession turns the suspect's feeling of moral guilt into legal guilt.

　　· Police sometimes emphasize that a confession will speed things up. Many suspects, especially first-time offenders, want to put a criminal charge behind them as soon as possible. To them, a confession represents the shortest line between two points.

　　· Police officers tell suspects that ''we'll put what you say in our reports, so this is a chance to make sure that the district attorney hears your side of the story." Uselessly trying to minimize their guilt, suspects often furnish evidence that eventually helps convict them.