USC research is mapping out areas of the brain responsible for deception

Polygraphs, P300 brainwaves, and micro expressions

Pinocchio telegraphed his lies by conveniently adding length to his wooden nose. Our noses don’t grow, of course, but we often betray our deceit by fidgeting, sweating, and blinking.

Those symptoms are what traditional polygraph tests detect.

“Polygraph testing, which has been used since the 1920s, looks at changes affected by the peripheral nervous system—skin conductivity, respiration, heart rate—as correlates to whether someone is telling the truth,” said USC psychology researcher Jennifer Vendemia.

Put another way, the peripheral nervous system creates a response to deception while the lie is being told—perhaps in the form of heart rate changes or perspiration. The police investigator asks a suspect if he robbed a bank—the suspect answers “No,” and his heart rate increases.

Polygraph testing, when expertly conducted, has a high rate of accuracy, but it’s not 100 percent.

Like many other deception researchers around the country who are hoping to find a more reliable means of lie detection, Vendemia is focusing on electrical activity in the brain. Other researchers are studying brain blood flow to see which areas receive more blood flow during interrogation.

Still others focus exclusively on P300 brain waves, which are associated with recognition of embedded memories. In 2000 an Iowa judge ruled there was sufficient scientific basis to admit brain wave data as evidence in the case of a convicted murderer seeking a retrial. His brain wave testing suggested he was not familiar with key details of the crime for which he was convicted.

But P300 brain waves alone are too narrow a focus, USC’s Vendemia said.

“We did a study on murderers here [in Columbia] and found that they often don’t have normal brain wave forms,” Vendemia said. “We think it’s because of the environment of death row.”

Other researchers have focused on so-called micro facial expressions—the subtle twitches, blinks, and tics that accompany telling a lie. The goal is to pair computers with video cameras to map out the spectrum of expressions a person exhibits while telling truths and lies. Unfortunately, the concept of micro expressions hasn’t been objectively verified by more than one scientist.

The holy grail of deception research is to find a brain wave or some other neural signal associated with lying that cannot be consciously altered by the subject. For now, the searchcontinues.
The Pinocchio Effect

By Chris Horn

A liar’s nose doesn’t grow longer—but a USC psychology researcher is tracking other telltale signs of deception embedded in the human brain.

If you’ve ever watched NYPD Blue, that hardy perennial of TV cop shows, you know that homicide detective Andy Sipowicz has an uncanny ability to extract the truth from lying suspects.

Those TV-land murderers are guilty as hell, of course, but they always start out lying through their teeth: “Wasn’t there… never seen the victim before… You’ve got the wrong guy.”

Yeah, yeah. After a few well-aimed questions (and the occasional punch) from Det. Sipowicz, they nearly always ’fess up.

Ah, if it were only so easy to get the truth. As Shakespeare’s Falstaff lamented, “Lord, Lord, how this world is given to lying!” USC psychology professor Jennifer Vendemia can identify. She has studied nearly every form of chicanery, and her research on human deception has made her a national authority on the subject. Not incidentally, Vendemia’s work is attracting mega funding from the federal government.

“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.”

So how do you know if the person applying for an airport baggage-screening job is falsely denying his terrorist connections? The answer lies not in searching the black heart of deceit but in understanding the anatomical wiring of the human mind.

“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 three years of deception studies at USC, 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.”

It might be a civil lie—we say we’re fine when our little world is in shambles—or it might be a defensive lie, the kind people tell for protection when being interrogated.

Which brings us back to the hypothetical baggage handler/terrorist. If he practices lying enough, won’t he getpretty good at it—perhaps good enough to evade a lie detector test in a job interview? Well, he will get better at lying, just as all of us improve on the bungling attempts at lying that begin in childhood (“I didn’t spill my drink on the couch—the cat did it!”). The real question is, can humans perfect lying to the point that their brains work as smoothly and quickly as when telling the truth?

The answer is no.

“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.
“We’re not sure yet why that is, but we think there must be a certain number of actions that have to take place in the brain to tell a lie. We’re pretty sure it’s linked to working memory and the limited ability to store information there.”

Some of Vendemia’s experiments involve subjects who commit staged “crimes” and then are questioned about their activity. These staged crime scenarios have involved a subject entering the office of a fictitious professor and stealing files that are handed off to a student on another floor of the building. The idea is to imprint a sequence of events in the subject’s memory that must be accessed when the subject is questioned later.

“Even though they know they haven’t committed a real crime, we have the subjects do certain things that are embedded in their memories. We’ll study the brain activity that occurs when we ask them questions that make them remember those events,” Vendemia said.

To track the neural activity of lying, Vendemia and her research team place a hairnet-type contraption containing dozens of tiny electrodes on subjects’ heads. The device measures brainwave activity and pinpoints the location of each node of activity. This generates an enormous amount of data in the typical deception-measuring experiment.

“At its heart, this is a big math problem,” Vendemia said, noting that she has added a physicist to her research team to help tackle the reams of brain-wave data.

All of this experimenting and data crunching has led Vendemia to construct her own theory of deception. It’s a multi-step pathway that includes a motivation to lie, individual personality, learning history (was the subject disciplined/rewarded for lying in the past), and memory. Her theory is scheduled for publication this year in the scholarly journal Behavioral Neurology.

Because memory plays a major role in deception—a thief must “choose” to ignore memories of a crime when telling a lie, for example—Vendemia plans to further explore this aspect of the brain. In a planned experiment, volunteer subjects will watch a video of a crime, then read a story about the crime that includes details that are different from what they watched. Subsequent questioning will determine if subjects remember the false details as vividly as the true ones.

As Vendemia’s research expands, she and her team will continue studying the neural pathways that are activated during truth- and lie-telling and explore possible strategies that might allow someone to mask their lying brainwaves.

Much more work needs to be done before a model of this research will be available for broad use and becomes admissible evidence in court. But the potential remains high for a neurological approach to ferreting out the truth. If successful, Vendemia’s work and that of other deception researchers could give law enforcement agencies a powerful new strategy for questioning suspects and screening applicants for security-sensitive jobs.

In the end, verifying truth might be our nation’s most important strategy for national security and terrorism defense.