University of South Carolina

Human brain activity is key in deception research


This article appears in the newest edition of Breakthrough Magazine, a publication that focuses on research and economic development at the University of South Carolina. 

In the Fox Network TV show Lie to Me, Dr. Cal Lightman and his intrepid team figure out who is lying by spotting subtle body language cues and using their nifty Facial Action Coding System to detect microexpressions.

Twitch your eyebrows or tighten your jaw in front of those guys, and you're dead meat. They always catch the liars.

In real life, detecting deception isn't so easy. Real experts on deception will tell you that microexpressions and body language make for entertaining TV scripts but haven't been objectively verified for lie detection purposes. Even polygraph tests, though their track record is far more extensive, aren't admissible in court.

Jennifer Vendemia
Jennifer Vendemia

It turns out the real answer to detecting deception is to search -- not in the black heart of deceit -- but in the neurological wiring of the human mind. That's what Carolina psychology professor Jennifer Vendemia has been doing for several years, and her research, currently funded with $5.1 million from several federal agencies, has turned up some interesting facts.

"We're mapping out the areas of the brain that are involved in deception," Vendemia said, "and looking for the precise brain-wave activity that occurs at the moment a person decides to deceive."

In more than six years of deception studies at the University of South Carolina, Vendemia's research group has been able to isolate, by analyzing brain waveforms of volunteer subjects, the exact instant when a person decides to lie. It's a fleeting moment-only a half-second long-that occurs just after a question is asked by an interrogator and before the subject's verbal response.

"What we're finding is that there is no naughty spot in the brain where the decision to tell a lie originates," Vendemia said. "There are multiple regions, and it's very individualized how each person's brain works.

"What's common for all of us, though, is that lying involves a decision. In the space of 800 milliseconds or so, we decide to inhibit a truthful response and give a deceptive response to a question."


Vendemia's research attracted immediate interest from the federal government in the wake of the 2001 terrorist attacks.

"Screening employees is the federal government's No. 1 motivation for supporting deception research," said Vendemia, whose work has been funded by the U.S. Department of Defense's Polygraph Institute and the National Science Foundation. "The goal is to keep terrorists from infiltrating and undermining the nation's security agencies."

Vendemia's research group used EEG instruments in its early research to map out brain activity; now they also use a powerful Tesla 3 fMRI machine purchased with a research grant and housed at the McCausland Center for Brain Imaging. More than 200 people have been scanned with the device to further the deception research.

What have they found so far?

"We know that someone with a large, active memory has the ability to hold lots of new information, and that person is better at being deceptive," Vendemia said. "Their fMRI scans show that the areas of the brain associated with deception don't light up as fast as with someone who doesn't have the same memory ability."
But the brain activity associated with the decision to tell a lie is revealed on the brain scan, and even the most practiced and casual of lies--telling someone you're fine when you're really not--still shows up on an fMRI scan.

"Quite simply, it takes longer to lie than to tell the truth," Vendemia said. "Of all the studies I've done, this one has produced some of the strongest data I've ever had."

Vendemia's brain scanning can distinguish between someone who is incorrectly remembering something and deliberately deceiving. In fact, a person can be tricked into unintentionally lying by erasing bits of their original memory. Research experiments that involve replacing key details of a crime scene with false information, for example, can alter someone's memory of what they saw. "It shows how key witness testimony can be false," Vendemia said.


Vendemia has collaborated with psychology department colleague Tawanda Greer to use fMRI scans to detect brain activity associated with racist attitudes. And she is hoping to expand her deception research by exploring cultural differences in lying.

"In cultures that are more group oriented, there is more deception," Vendemia said. "A study that involved Canadian and Chinese subjects showed that there are fewer reasons to lie as an individual than as part of a group.

"We have what we call white lies-little deceptions that make life more convenient or smooth like telling someone they look fine when they really don't. In India there are blue lies, which one tells to protect a family name. There are different reasons to lie and it's partly tied to personality and culture."

Vendemia traveled to China earlier this fall to begin exploring ways to begin her cross-cultural research on deception.

But the bread-and-butter research on deception is driven by homeland security.

"In the screening world, the big questions they want to ask are along the lines of, ‘Are you the kind of person who might... ?'" Vendemia said. "In other words, a person might not be a secret terrorist, but he or she might have personality quirks that might make them prone to become one or to act out in some dangerous way.

"Those are the most difficult questions to map out from our perspective because you're asking about nebulous concepts. We can measure the decision to tell a lie with fMRI, but we can't map out someone's thought processes. There is far more to be discovered than what's been found so far."

Posted: 11/11/09 @ 12:00 AM | Updated: 08/09/11 @ 9:12 AM | Permalink