If someone confesses to a crime, it doesn’t necessarily mean that they’re guilty. In 25% of convictions reversed with DNA evidence by the Innocence Project, the convicted person had made a false confession.
While this might not be common knowledge among the general public, one would hope that it’s widely known among those working in law enforcement. But a recent study published in Police and Criminal Psychology shows that police officers are no less likely to believe policing myths than anyone else.
Chloe Chaplin, from London Probation Services in the UK, and Julia Shaw, criminology lecturer at London South Bank University, asked 100 people (44 who worked as British police and law enforcement officers and 56 who did not) to evaluate the accuracy of several statements, which included 50 major misconceptions. Such false statements included: “police can tell when a suspect is lying,” “people only confess when they have actually committed the crime they are being charged with,” and “if you are the victim of a violent crime, your memory for the perpetrator’s face will be perfect.”
Unfortunately, police proved no better than civilians at judging the accuracy of such statements.
Police officers rated an average of 18 of the false statements as true, compared to an average of 19 endorsed by those outside law enforcement. “After statistical correction for repeated tests, no single item on the questionnaire showed a significant difference in endorsement for lay and legal participants,” write the authors. Plus, the police officers rated themselves as more confident in their belief that the statements were correct than non-police.
Shaw tells Quartz that the findings are evidence of a science-practitioner gap—and that if it’s true for UK police, it almost certainly exists in other police forces.
“Given that the UK has one of the most evidence-based forces in the world, I am confident that police from other places, including the US, would have even worse accuracy rates,” she says. “The British police are aware that they have misconceptions, they often just don’t know where to start when it comes to training. US police, however, often deny the fact that there may be important issues that they don’t understand, including often not accepting that many of their lie detection and memory interview practices are fundamentally flawed.”
One major reason why police officers may be inclined to disregard evidence is confirmation bias, says Shaw, where officers only remember information in line with their existing beliefs.
“For example, many police think they are good at detecting deception. The research, however, shows that most police officers are no better than chance at spotting liars. This discord happens because police only remember the times they were accurate, and easily forget the times that they were wrong—the times they called innocent people liars,” she adds.
The sample size is relatively small, but Shaw points out that it’s difficult to persuade police officers to participate in such surveys. The study provides a glimpse into “the minds and biases of police,” she says, though there’s still a need to examine misconceptions of more police forces around the world.