In criminal trials, a defendant's admission of guilt can trump even the proverbial smoking gun. A confession is the ideal civic solution: The perpetrator takes responsibility, and the public sleeps soundly. But it's not always the end of the story. The convictions of five men who confessed to the 1989 rape and beating of a jogger in New York's Central Park were reversed after an imprisoned rapist took sole responsibility for the assault. Governor George Ryan commuted the sentences of Illinois' 150 death-row inmates to life in prison, due in part to concern about the role of false confessions in securing wrongful convictions.
Although it is difficult, if not impossible, to estimate the number of false confessions nationwide, a review of one decade's worth of murder cases in a single Illinois county found 247 instances in which the defendants' self-incriminating statements were thrown out by the court or found by a jury to be insufficiently convincing for conviction. (The Chicago Tribune conducted the investigation.)
Suspects with low IQs are particularly vulnerable to the pressures of police interrogation: They are less likely to understand the charges against them and the consequences of professing guilt. One of the suspects in the Central Park attack had an IQ of 87; another was aged 16 with a second-grade reading level.
But intelligence is by no means the decisive factor. Suspects with compliant or suggestible personalities and anxiety disorders may be hard-pressed to withstand an interrogation, according to Gisli Gudjonsson, Ph.D., a professor of forensic psychology at the Institute of Psychiatry in London. Gudjonsson's suggestibility scale is used by courts around the world to evaluate self-incriminating statements. But he cautions against seeking only personality-driven explanations for confessions: "A drug addict may not be particularly suggestible but may have a strong desire to get back out on the street."
Self-incriminating statements are often the result of a kind of cost-benefit analysis. "False confession is an escape hatch. It becomes rational under the circumstances," says Saul Kassin, Ph.D., a professor of psychology at Williams College in Massachusetts. The most common explanation given after the fact is that suspects "just wanted to go home."
This often indicates an inability to appreciate the consequences of a confession, a situation that police cultivate by communicating that a confession will be rewarded with lenient sentencing. Police may also offer mitigating factors—the crime was unintentional; the suspect was provoked.
The circumstances of interrogation are crucial. "Everybody has a breaking point. Nobody confesses falsely in an hour," says Kassin. The suspects in the Central Park case each spent between 14 and 30 hours under interrogation.
The use of false evidence (including statements such as, "Your fingerprints are on the gun") in interrogation is implicated in almost every false-confession case, but American courts have upheld the practice. This is not to say that police intentionally ensnare the innocent. Kassin notes that detectives are trained to believe they can make accurate judgments about a suspect's truthfulness, though "there's a level of overconfidence in the initial judgment, and they begin the interrogation with a presumption of guilt." Gudjonsson agrees: "Police officers need to know that they can elicit a false confession even if they don't intend to."
A particularly vulnerable defendant may begin to doubt his or her own memory when presented with false evidence. Children and the mentally handicapped, or people whose recollections are clouded by drugs or alcohol, are particularly susceptible. Interrogators may suggest that a suspect has repressed the memory. They then offer false evidence to fill in the gaps. After intense interrogation, these suspects become sufficiently convinced of their own guilt and accept an "internalized" false confession.
False confessions are generated in cell blocks as well as interrogation rooms, a fact not lost on detectives under fire for the Central Park jogger case. One month after those convictions were vacated, a chagrined New York City Police Department issued its own revisionist theory: The inmate who claims he alone attacked the jogger may have falsely confessed due to threats from other inmates or the desire to transfer to another prison.