August 15, 2014 |
Non-experts have high rates of success of lie detection when viewing experts work
Determining deception is a tool of the trade for law enforcement. The Good Cop/Bad Cop routine is etched in our minds as an effective method of finding out the truth. But prior research has shown that lie detecting is a 50/50 shot for experts and non-experts alike. So what exactly can we do to find out the truth? A recent study published in Human Communication Research by researchers at Korea University, Michigan State University, and Texas State University – San Marcos found that using active questioning of individuals yielded near-perfect results, 97.8%, in detecting deception.
Timothy Levine, Hee Sun Park (University of Korea), David Daniel Clare, Steve McCornack, Kelly Morrison (Michigan State University), and J.Pete Blair (Texas State – San Marcos) published their findings in the journal Human Communication Research. The researchers conducted three studies based on sets of participants who were asked to play a trivia game. Unbeknownst to the participants, a confederate was placed with them offering an incentive and opportunity to cheat at the game, since cash prizes were involved. In the first experiment 12% of the subjects cheated; in the second experiment 44.9% cheated.
An expert using the Reid Technique interrogated participants in the first study, this expert was 100% accurate (33 of 33) in determining who had cheated and who had not. That kind of accuracy has 100 million to one odds. The second group of participants were then interviewed by five US federal agents with substantial polygraph and interrogation expertise. Using a more flexible and free approach (interviews lasted from three minutes to 17 minutes), these experts were able to accurately detect whether or not a participant cheated in 87 of 89 interviews (97.8%). In the third study, non-experts were shown taped interrogations of the experts from the previous two experiments. These non-experts were able to determine deception at a greater-than-chance rate – 79.1% (experiment 1), and 93.6% (experiment 2).
Previous studies with “experts” usually used passive deception detection where they watched videotapes. In the few studies where experts were allowed to question potential liars, either they had to follow questions scripted by researchers (this study had no scripts) or confession seeking was precluded. Previous studies found that accuracy was near chance – just above 50%.
“This research suggests that effective questioning is critical to deception detection,” Levine said. “Asking bad questions can actually make people worse than chance at lie detection, and you can make honest people appear guilty. But, fairly minor changes in the questions can really improve accuracy, even in brief interviews. This has huge implications for intelligence and law enforcement.”
Levine’s findings have led him to develop a new theory, Truth Default Theory. Levine’s idea is that when humans communicate with other humans, they tend to operate on a default presumption that what the other person says is basically honest.
“The presumption of honesty is highly adaptive. It enables efficient communication, and this presumption of honesty makes sense because most communication is honest most of the time. However, the presumption of honesty makes humans vulnerable to occasional deceit” Levine said. “There are, of course, times and situations when people abandon this presumption of honesty, and the theory describes when people are expected to suspect a lie or conclude that a lies was told, and the conditions under which people make truth and lie judgments correctly and incorrectly.”