Iowa State psychologists Stephanie Madon (far right) and Max Guyll (middle right) have been overseeing experiments -- like this one by ISU students Shelby Wuebker and Lee Casavant -- on the consequences that drive a person's confession decisions. Credit: Bob Elbert, News Service (download print quality photo)

Why would anyone falsely confess to a crime they didn't commit? It seems illogical, but according to The Innocence Project, there have been 266 post-conviction DNA exonerations since 1989 -- 25 percent of which involved a false confession.

A new Iowa State University study may shed light on one reason for those false confessions. In two experiments simulating choices suspects face in police interrogations, undergraduate subjects altered their behavior to confess to illegal activities in order to relieve short-term distress (the proximal consequence) while discounting potential long-term (distal) consequences.

"The thing about these exoneration cases is that they all pertained to heinous crimes; that's why there was DNA evidence available. And so we wanted to determine why someone may be willing to falsely confess to one of those crimes," said Stephanie Madon, an ISU associate professor of psychology and the study's lead author. "We thought it might have to do with the pay-off structure of police interrogations. Some interrogation methods -- like physical isolation and the presentation of false evidence -- have immediate consequences for suspects that encourage them to confess. Though they also face consequences that encourage them to deny guilt -- such as the possibility of conviction and incarceration -- these consequences are more distal.

"So the suspect is weighing these two consequences at once and that's going to shape their behavior," she continued. "That's what we were interested in understanding. Which of these consequences is going to influence confession decisions -- those that are happening right now, or the ones that may happen in the future?"

ISU study published in Law and Human Behavior

Iowa State researchers Max Guyll, an assistant professor of psychology; Kyle Scherr, a psychology graduate student; Sarah Greathouse, a former assistant professor of psychology; and Gary Wells, Distinguished Professor of psychology; collaborated with Madon on the study. It will be posted online this week by the journal Law and Human Behavior.

In the first experiment, 81 (38 women, 43 men) ISU psychology undergraduates were interviewed about their prior criminal and unethical behaviors, with their admissions and denials each paired with proximal or distal consequences. The proximal consequence was having to answer a long set of repetitive questions. The distal consequence was having to meet with a police officer in several weeks to discuss their answers in detail.

Researchers found that participants shifted their admissions to avoid the short-term consequence of repetitive questions.

"What we found is that our participants clearly made admission decisions on the basis of the proximal consequence," Madon said. "They would admit to having done some criminal or unethical behavior in order to avoid answering repetitive questions. And they did that even though they knew that it increased the likelihood that they would have to meet with the police officer in several weeks to discuss their answers in more detail."

In the second experiment, 143 (93 women, 50 men) ISU psychology undergraduates were again interviewed about their prior criminal and unethical behaviors. This time, the proximal and distal consequences were reversed from the first experiment. So the proximal consequence was meeting with the police officer immediately after the interview, while the distal consequence was to return to the lab in several weeks to answer the repetitive questions.

"Once again, the participants' admissions were shaped by the proximal consequences. They did not want to meet with the police officer," Madon said. "And so, they responded in a way that got them out of doing that -- even though it increased their likelihood of coming back in several weeks to answer repetitive questions."

Suspects confess to avoid a police interrogation

The researchers say these results may help explain why some suspects confess to crimes in order to avoid a police interrogation -- even though they increase their risk of conviction and severe penalties by doing so. The study's authors theorize that innocent suspects so strongly believe that the truth will eventually be borne out, they may perceive the distal consequences facing them -- conviction, prison, or even a death sentence -- to be remote and unlikely.

"One of the things we wanted to do in this research was to identify an underlying process at play during interrogations, so it can apply to a variety of police interrogation methods," Madon said. "Our findings have implications for any [police interrogation] method that causes suspects to focus on immediate consequences over future consequences."

Madon sees the results underscoring the need to limit the use of police interrogation methods that may exploit suspects' vulnerabilities and encourage them into making confession decisions on the basis of short-term gains.

Explore further Exonerations correct only a small fraction of false convictions