Detecting Liars by Content
Kevin Colwell, a psychologist at Southern Connecticut State University, has advised police departments, Pentagon officials and child protection workers, who need to check the veracity of conflicting accounts from parents and children. He says that people concocting a story prepare a script that is tight and lacking in detail.
“It’s like when your mom busted you as a kid, and you made really obvious mistakes,” Dr. Colwell said. “Well, now you’re working to avoid those.”
By contrast, people telling the truth have no script, and tend to recall more extraneous details and may even make mistakes. They are sloppier.
In several studies, Dr. Colwell and Dr. Hiscock-Anisman have reported one consistent difference: People telling the truth tend to add 20 to 30 percent more external detail than do those who are lying. “This is how memory works, by association,” Dr. Hiscock-Anisman said. “If you’re telling the truth, this mental reinstatement of contexts triggers more and more external details.”
Not so if you’ve got a concocted story and you’re sticking to it. “It’s the difference between a tree in full flower in the summer and a barren stick in winter,” said Dr. Charles Morgan, a psychiatrist at the National Center for Post-Traumatic Stress Disorder, who has tested it for trauma claims and among special-operations soldiers.
This is new research, and there are limitations to the approach, but it’s interesting.