How Stress Can Lead To False Confessions

If you were wrongly accused of a crime, would you feel stressed out? Probably you would, but the innocent are often less stressed than the guilty, Iowa State University researchers found. That could leave you at more risk to admit to a crime you didn’t commit.

To understand what leads to false confessions, researchers measured assorted stress indicators, including blood pressure, heart rate and nervous system activity. In the study, stress levels increased for all participants when they were first accused. But the levels for those wrongly accused were appreciably lower. That is a concern, since it can make the innocent less likely to forcefully defend themselves during interrogation.

Manipulating the Innocent

“The innocent are less stressed because they believe their innocence is going to protect them and they think everything is going to be OK, so there is no reason to get worked up over this accusation,” said associate psychology professor Stephanie Madon. “But if you’re going into a police interrogation and you’re not on your guard, then you could make decisions that down the line will put you at risk for a false confession. Because once you talk to police, you’re opening up the chance that they’re going to use manipulative and coercive tactics.”

Minimization is one of the tactics used in interrogations and the tactic the researchers used in their study. By minimizing the severity of a crime, assistant psychology professor Max Guyll explained how investigators try to persuade the person they are questioning that it is in his or her best interest to confess. At first, it is easier for the person to defend themselves, but over time they start to wear down.

“If you’re brought in late at night and kept for several hours, you’re exhausted, and you have these investigators who are in a position of power. They’re challenging everything you say and they’re not accepting anything you say,” Guyll said. “That pressure starts to take a toll physiologically and there’s a greater chance you’ll give up and confess.”

Wearing Down Tactics

Prior research has studied false confession cases where police kept track of the length of the interrogation. In those cases, they found people were questioned for up to 16 hours on the average before admitting to a crime they did not commit.

“These people held out for a very long time, but they couldn’t hold out forever,” Madon said. Interrogations usually only last 30 minutes to 2.5 hours. But with some false confessions, suspects were questioned for up to 24 hours.

“Being in a police interrogation is a very powerful situation,” Guyll said. “If you wear a person down you can probably get false confessions.”

If questioned for a long period of time, the expenditure of resources can begin to take a toll, Guyll explained. As a result, it causes even more of the innocent to lose their energy and motivation to continue defending themselves, ultimately leading them to give up and confess.

“Everyone’s resources are drained over time, and this is made even worse when investigators constantly pressure the suspect and dispute their story,” Guyll said. “If you’ve ever been in an hour-long argument with someone, just think how exhausting that is, and how you get to a point where you will say you are wrong just to make it stop. Now imagine that argument going on for 16 hours.”

Image: Shelley James, Wellcome Images