Sacramento Bee staff writer Ralph Montaño reports. Excerpt:
Douglas Mansfield and Jeannie Overall know when you’re lying.
Both have spent 20 years watching for the telltale signs: a jumpy pulse, a sweaty palm or a pause before a breath.
As polygraph examiners for the California Department of Justice, they spend most of their time asking questions about murder, kidnapping and child molestation. Combined, they average about 400 tests a year, traveling from one city to the next.
The recent disappearance of former intern Chandra Levy in Washington, D.C., and her connection with Rep. Gary Condit, D-Ceres, have increased focus on the polygraph field as the merits of lie-detector machines are debated.
The state attorney general’s office has provided a polygraph exam service to law enforcement agencies across the state since the 1970s. Without the service, many of the state’s small police departments couldn’t afford such an exam.
Polygraphs aren’t perfect, authorities say. But when combined with proper interview techniques, they can provide criminal investigators with key clues and confessions.
“You would be surprised how many people just confess … during interviews,” Mansfield said. “The interview is just as important as the test itself.”
Douglas Mansfield and Jeannie Overall don’t know when you’re lying. They can only guess. The article goes on to note that the Sacramento County Sheriff’s Department has adopted the cheaper competing pseudoscience of voice stress analysis.