False confessions are a real danger in the criminal justice system. According to the National Registry of Exonerations, 12% of all exonerations since 1989 involved a false confession. According to the Innocence Project, that number goes up to 62% when considering people who were convicted of murder but later cleared by DNA.
Yet some police interrogation techniques make false confessions more likely. The classic “third degree,” which amounts to torture, was used to convince many innocent people to confess to crimes.
But police interrogations are more sophisticated now, right? Not necessarily.
Although it is true that torture is much less common than it once was, police are still desperate to find a way to determine who is telling the truth. The problem is, there simply are no techniques that increase a human being’s ability to distinguish lies at a rate greater than average.
“A lot of ‘police science’ is really pseudoscience,” says Steven Drizin, a Northwestern University professor who studies false confessions. “Police officers do believe that they’re able to detect liars from truth-tellers at much higher rates that you and I are. And that’s just been proven not to be the case.”
But that fact hasn’t stopped pseudoscientists from profiting off of the police’s need to be able to distinguish truth from lies. According to the award winning investigative newsroom the Intercept, a number of police trainers promise to help officers do better at lie detection.
The information about the trainings comes from BlueLeaks, a set of leaked police files posted online and analyzed by the Intercept.
Micro-expressions and neurolinguistic programming are bogus
Most of the trainings the Intercept examined involved things like micro-expressions or behavioral cues, which allegedly allow a trained observer to detect deception. Others involved “neurolinguistic programming,” which purports to use unconscious eye movements to reveal lies. Unfortunately, all of these have been thoroughly studied by scientists and found to provide no better insight than chance.
The techniques rely in large part on the hunches and contextualization offered by the officer. As such, they are subject to bias and misinterpretation.
Some of the trainings claim that the techniques make it possible to distinguish truth from lies upward of 85% of the time. Yet scientists interviewed by the Intercept challenged each one as essentially useless or even bogus.
Unfair interrogation techniques hurt police credibility
As the nation comes to a reckoning about police, it is crucial for police forces to use only scientifically valid interrogation techniques.
“Part of the distrust that you see between law enforcement and minority communities stems from the way that suspects, witnesses, victims, and family members are treated by detectives during the course of an investigation,” points out Steven Drizin.