A false confession is, just as the name implies, a confession to a crime made by an accused that is not accurate, or in many cases, completely fabricated.
Everyone can get their head around the idea of someone lying to avoid punishment. But wrongly implicating yourself? The very notion is so alien to most people that they have no sympathy for the person in question. No one can envision themselves doing something so "stupid" so they have little time for trying to understand why anyone else would do such a thing.
Beat it Out of Him
Almost without fail, false confessions are elicited by police officers who subject the accused to brutal interrogation over lengthy periods of time—sometimes days on end. The subject is broken down and then the new reality is planted in his mind in which he is the guilty party. The individual truly comes to believe that he was involved in the crime.

Police decide early on in an investigation who they think the guilty party is, and then search for any evidence that supports their beliefs. When there is a confession, this absolute conviction in their minds becomes invincible.
Mistakes were Made (but not by me)
In the book, Mistakes Were Made (but not by me) the authors go into detail about how false confessions come about:
The bible of interrogation methods is Criminal Interrogation and Confessions, written by Fred E. Inbau, John E. Reid, Joseph P. Buckley, and Brian C. Jayne. John E. Reid and Associates offers training programs, seminars, and videotapes on the 9-Step Reid Technique, and on their Web site they claim that they have trained more than 300,000 law-enforcement workers in the most effective ways of eliciting confessions. The manual starts right off reassuring readers that "none of the steps is apt to make an innocent person confess," and that "all the steps are legally as well as morally justifiable":
It is our clear position that merely introducing fictitious evidence during an interrogation would not cause an innocent person to confess. It is absurd to believe that a suspect who knows he did not commit a crime would place greater weight and credibility on alleged evidence than his own knowledge of his innocence. Under this circumstance, the natural human reaction would be one of anger and mistrust toward the investigator. The net effect would be the suspect's further resolution to maintain his innocence.
Wrong. The "natural human reaction" is usually not anger and mistrust but confusion and hopelessness—dissonance—because most innocent suspects trust the investigator not to lie to them. The interrogator, however, is biased from the start. Whereas an interview is a conversation designed to get general information from a person, an interrogation is designed to get a suspect to admit guilt. (The suspect is often unaware of the difference.) The manual states this explicitly: "An interrogation is conducted only when the investigator is reasonably certain of the suspect's guilt." The danger of that attitude is that once the investigator is "reasonably certain," the suspect cannot dislodge that certainty. On the contrary, anything the suspect does will be interpreted as evidence of lying, denial, and evading the truth, including repeated claims of innocence. Interrogators are explicitly instructed to think this way. They are taught to adopt the attitude "Don't lie, we know you are guilty," and to reject the suspect's denials. We've seen this self-justifying loop before, in the way some therapists and social workers interview children they believe have been molested. Once an interrogation like this begins, there is no such thing as disconfirming evidence.
That is the most disturbing thing about false confessions. Even when it has been proved that someone did not commit a crime to which they have falsely confessed, the police who were involved in eliciting that confession rarely, if ever, see the light and admit their mistake.
Referring to innocent people freed from prison (and in these cases, not just due to false confessions) the authors of Mistakes were Made write:
Of all the convictions the Innocence Project has succeeded in overturning so far, there is not a single instance the police later tried to find the actual perpetrator of the crime. The police and prosecutors just close the books on the case completely, as if to obliterate its silent accusation of the mistake they made.
In the light of DNA evidence, eyewitnesses admitting they lied, and numerous other indications that they had the wrong person, the police never decide to seek the person who actually did commit the crime. It is quite a sickening realization that police, lawyers, and others within the justice system, are more motivated by justifying their behaviour and saving face than getting at the truth.
The false confession is far more common than most people could imagine. Within police forces, every action and utterance is validated and justified by a subculture that convinces its members that they can do no wrong. As with all instances of self-justification by humans, when all facts point to police officers being wrong about someone from whom they have elicited a false confession, the likelihood of them seeing the light and trying to right the wrong is almost non-existent.
A Different Type of False Confession
Kyle Unger was recently acquitted after serving 14 years in prison for a crime that he didn't commit. He was convicted largely on the basis of a confession he made to undercover police officers posing as gang members. Unger made the confession to impress the "gang members" in the hopes that he would have the chance to work with them. However, the confession contained numerous details that police knew were false. In the light of evidence to the contrary, they latched on to the confession and sent him away for close to 15 years.
The attorney general in Manitoba has stated that there will be no compensation forthcoming.
The false confession should not disqualify Unger for compensation, just as no other single consideration should disqualify a wrongly incarcerated person for compensation. It's as if we are saying that only those who didn't break under interrogation and long years in prison for a crime that they didn't commit should be compensated for those lost years. This is ridiculous. Lost years are lost years regardless of how the person is wrongly convicted and sent to prison. The blame should not be placed on the person who was interrogated, coerced, and yes, in some cases, tortured into making a false confession.
The false confession has become a way for prosecutors and police forces to absolve themselves of any blame when a wrongly incarcerated person is freed. More importantly, it is a way for governments to avoid paying compensation to people who have sacrificed years, and sometimes decades, of their lives. All because of the arrogance and short-sightedness of police forces that leaned on a suspect until he broke and then, with the assistance of a prosecutor, rode the false confession to a conviction despite all evidence to the contrary.
No police officer wants to be told that something he considers to be a valuable tool—interrogation— in his arsenal against criminals is likely to send a good number of innocent people to prison. But we need to pay more attention to the phenomenon of false confessions, or they will continue to send innocent people to prison, and the reputation of police forces will continue to suffer.