Kinder, gentler: How to get an innocent person to confess to a crime

Long story short: "Make a kindly suggestion of guilt."

And: "The more plausible the alleged act... the likelier the false confession."

The May 2008 issue of The Atlantic magazine featured an item about a recent study in the psychology literature about guilt and confession in its "Primary Sources" feature; the piece follows.

Confessions of a Non-Dangerous Mind

The best way to get someone to confess to a crime may be to make a kindly suggestion of guilt — even if the suspect is innocent. Three researchers gathered 219 students and asked them to take a typing test. The subjects sat at computers and typed out letters read aloud by the experimenter. Some of the participants were warned that if they pressed the Alt key, the program would crash and all the data would be lost. The system was rigged so it would shut down after the experimenter asked the participants to type the Z key (which sits just to the left of the Alt key). The experimenter then interviewed the volunteers individually and asked each to sign a statement admitting he or she had ruined the test. “Don’t worry,” the experimenter said. “You didn’t mean to hit the Alt key. Several participants so far have pressed the Alt key during this task. Are you sure you didn’t press it?” Seventy percent of the participants — all innocent — eventually confessed. The professors then repeated the experiment, substituting the Esc key for the Alt key. But since the Esc key sits much farther away from the Z key, only 23 percent of participants admitted to hitting it. The more plausible the alleged act, the authors conclude, the likelier the false confession. The study also found that participants in both tests who were interrogated in a more intimidating manner (“It looks like the entire project may be delayed now. Why did you press the key?”) were less likely to falsely admit to the offense, suggesting that a light hand may be the best way to elicit a false confession.

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Here's the abstract of the paper, which appeared in the February 2008 issue of Legal and Criminological Psychology.

Effects of personality, interrogation techniques and plausibility in an experimental false confession paradigm

Purpose: The goal of the present study was to investigate the effects of personality variables, interrogation techniques and the plausibility level of an alleged transgression on the experimental elicitation of false confessions.

Methods: Two hundred and nineteen undergraduate students assessed on measures of compliance, self-esteem, locus of control and interrogative suggestibility participated in the Kassin and Kiechel (1996) paradigm. Experimental manipulations included minimization and maximization interrogation techniques and high and low plausibility of the alleged typing mistake to examine rates of false confession and internalization.

Results: The overall false confession and internalization rates across all conditions were 43 and 10%, respectively. An increased likelihood of false confession behaviour was associated with higher Shift scores on the Gudjonsson Suggestibility Scale, the use of minimization interrogation techniques and an increase in the plausibility of the allegation. Females were more likely to falsely confess than males in the high plausibility condition, whereas Caucasian and Asian participants were equally likely to falsely confess. Personality variables, such as compliance, most influenced the behaviour of males and Asians.

Conclusions: The results of this study offer insight into false confession behaviour, suggesting that individuals who have a tendency to change their responses in the face of negative feedback may be more prone to false confession behaviour. The findings also serve to highlight the dangers of using minimization interrogation techniques and elucidate the limited generalizability of the paradigm to situations in which the alleged transgression is less plausible.