Liar Liar Pants on Fire

For now, those agencies rely on the polygraph. Recognizing the device's flaws, the government has begun to increase its funding for research into novel kinds of lie detectors-raising the visibility of what had been an obscure corner of science. "Nobody cared what I did two years ago," says South Carolina's Vendemia. "Now all of a sudden lots of people are investigating it."


Not all the research involves high-level brain experiments. For example, researchers at the Mayo Clinic have theorized that blushing around the eyes, detectable only by an infrared camera, is a sign of lying. To prove this, they asked eight volunteers to stab a mannequin, grab a $20 bill, and leave the room. Twelve others did nothing. Then all 20 participants had to try to convince interrogators that they didn't take part in the mock crime. Monitoring the subtle changes in temperature around the subjects' eyes, the scientists correctly identified six of the eight "guilty" subjects and 11 of the 12 "innocent" ones. Similar experiments have found that a split-second hesitation before answering a question is often an indication of lying-as is an almost indiscernible muscle twitch.


These types of lie detection techniques are appealing because they could let authorities test for duplicity quickly and secretly, without having to hook anyone up to a machine. They raise the possibility of, for instance, hidden airport sensors that surreptitiously scan the area around people's eyes for increased heat to determine whether they're telling the truth about what's in their luggage.




For now, though, the general attitude among federal agencies is that as new lie detection technologies emerge, they will likely be used to enhance the polygraph, which is a relatively inexpensive and simple way to test for the truth. Equipment for measuring eye blushing, hesitation, twitching, or even brain activity could be incorporated into the machine, says Andy Ryan, chief of research at the Department of Defense Polygraph Institute, which oversees polygraph examiners for federal agencies. Alternatively, these technologies, particularly high-priced and bulky equipment like fMRI scanners, could become the lie detection equivalent of a second opinion. "It's like taking a treadmill test to see if your heart is OK," says Ryan. "Your doctor would never diagnose heart problems from the results of a single treadmill test, which just offers a pattern subject to interpretation and further examination. It's the same way with a polygraph."


As investigators begin to unscramble the brain's role in deception and home in on more accurate ways to measure dishonesty, one thing is for sure: It will be a long time before we learn the whole truth about lying.