Category Archives: Airline security

Polygraph reasoning applied to spotting terrorists…

Remember that the rationale behind the polygraph is that (with an appropriate questioning regime) guilty people are assumed have physiological responses that differ from innocents? Well, the new “anxiety-detecting machines” that the DHS hopes might one day spot terrorists seem to work on the same basis. Here’s the report from USA Today (18 Sept):

A scene from the airport of the future: A man’s pulse races as he walks through a checkpoint. His quickened heart rate and heavier breathing set off an alarm. A machine senses his skin temperature jumping. Screeners move in to question him. Signs of a terrorist? Or simply a passenger nervous about a cross-country flight?

It may seem Orwellian, but on Thursday, the Homeland Security Department showed off an early version of physiological screeners that could spot terrorists. The department’s research division is years from using the machines in an airport or an office building— if they even work at all. But officials believe the idea could transform security by doing a bio scan to spot dangerous people.

Critics doubt such a system can work. The idea, they say, subjects innocent travelers to the intrusion of a medical exam.

According to the news report, there is some effort going into testing the equipment, though if the details in the news report are to be believed it sounds like the research is still at a very early stage:

To pinpoint the physiological reactions that indicate hostile intent, researchers… recruited 140 local people with newspaper and Internet ads seeking testers in a “security study.” Each person receives $150.

On Thursday, subjects walked one by one into a trailer with a makeshift checkpoint. A heat camera measured skin temperature. A motion camera watched for tiny skin movements to measure heart and breathing rates. As a screener questioned each tester, five observers in another trailer looked for sharp jumps on the computerized bands that display the person’s physiological characteristics.

Some subjects were instructed in advance to try to cause a disruption when they got past the checkpoint, and to lie about their intentions when being questioned. Those people’s physiological responses are being used to create a database of reactions that signal someone may be planning an attack. More testing is planned for the next year.

The questioning element does make it sound like what is being developed is a ‘remote’ polygraph.

Hat tip to Crim Prof Blog.

UPDATE: Lots of places picking this up all over the www. New Scientist has a post on the same topic here, and an earlier article on the system here. The Telegraph’s report adds some new information.

How to Spot a Terrorist on the Fly

Psychologist Paul Ekman has an article in today’s Washington Post (29 Oct) on his experience with the behavioural profiling TSA team at Boston Logan airport.

Critics of the controversial new security program I was taking stock of — known as SPOT, for Screening Passengers by Observational Techniques — have said that it is an unnecessary invasion of privacy, based on an untested method of observation, that is unlikely to yield much in the way of red-handed terrorists set on blowing up a plane or flying it into a building, but would violate fliers’ civil rights.

I disagree. I’ve participated in four decades’ worth of research into deception and demeanor, and I know that researchers have amassed enough knowledge about how someone who is lying looks and behaves that it would be negligent not to use it in the search for terrorists. Along with luggage checks, radar screening, bomb-sniffing dogs and the rest of our security arsenal, observational techniques can help reduce risks — and potentially prevent another deadly assault like the attacks of Sept. 11, 2001.

Read the whole article online here.

Weeding Out Terrorists: Officials Turn To Behavior Profiling To Find Would-Be Attackers

A reader (who prefers to remain anonymous) kindly pointed us towards this interesting article which appeared on the CBS news site on 15 August. It highlights the work of psychology Prof Mark Frank who is working, along with his former supervisor Paul Ekman, with the US TSA to develop methods of behavioural profiling.

While X-ray machines and explosive scanners focus on weapons, Transportation Security chief Kip Hawley said Tuesday that screeners are studying passengers for signs of nervousness. “It is involuntary muscular behaviors that are across the board, that doesn’t matter what you look like. You don’t have to look like a terrorist to exhibit these involuntary behaviors,” he says. It’s the first step in so-called behavioral profiling. The next step can be seen inside a lab at the University of Buffalo, where a research suspect is about to tell a lie.

[…] Frank, who’s developing the profiling technique for the Department of Homeland Security, claims he can spot a liar 90 percent of the time. “I think at this point it is at least as accurate as a polygraph,” he says. Frank says the kind of behavioral analysis he’s doing in his lab can be taught to screeners in the real world with as little as 30 minutes training. Hundreds of faces have convinced him the science is solid in identifying people who might be lying.

There are two videos on the site where you can see Frank discussing his work in more detail.

New-age lie detector takes a different tack

There’s an interview with Dr Britton Chance, Professor Emeritus of biophysics at the University of Pennsylvania, in the latest issue of the RCMP Gazette (Vol 68, No 2) entitled “Detecting deception” in which Chance outlines his team’s work to develop “a new-generation lie detector that measures deception by detecting sudden spikes in the brain’s bloodflow”. Here’s an extract:

How does this technology measure deceit?

Dr Chance: Deceit usually involves a decision to tell a lie instead of a decision to tell the truth. We can “image” this thought pattern before it’s articulated since it causes an increase in bloodflow to the cerebral cortex, or the brain’s decision-making centre. Users of the cognoscope detect changes in bloodflow through a red spot that appears on the computed images. I observed this relationship between bloodflow and deception in my work, as well as the work of my colleague, Dr. Daniel Langleben, an Assistant Professor of Psychiatry at the University of Pennsylvania.


There are many questions around the accuracy of conventional lie-detection techniques such as the polygraph. Could the use of near-infrared light sensors on the brain serve to boost the accuracy of lie detection techniques?

Dr Chance: Preliminary experiments with the cognoscope at the U.S. Department of Defense’s Polygraph Institute suggest the brain’s frontal cortex gives reliable signals. We have also proposed non-contact sensing of prefrontal activation, thus our optical method is one of the few, if not the only, technique that can be used-under proper ethical considerations-for remote sensing of brain functional activity. It is therefore suited for advanced government security tests, such as baggage handling checkpoints at airports. In this case, users could detect deception in passengers who are taken aside and asked if anyone else has handled their bags, etc.

Conclusions about the science of such technology are one thing, but implying that this sort of ‘brain scanning’ technology might be used for “advanced government security tests” at airports is, I believe, pretty irresponsible. It’s not suited for such an application, not now and not any time soon. I’ve written about overhyping of brain imaging techniques many times before so I’ll try not to repeat myself. But this article is in an official publication, which will be read by law enforcement officers throughout Canada and beyond. It’s a highly technical issue, but with no discussion on the limitations of such technology and no mention of the practical problems of ‘brain scanning’ suspicious individuals, how are readers with limited or no scientific background supposed to judge how useful this technology really will be?

Behavioural profiling at airports

The New York Times (16 August) provides more on behavioural profiling at airports:

[…] after the reported liquid bomb plot in Britain, agency officials say they want to have hundreds of behavior detection officers trained by the end of next year and deployed at most of the nation’s biggest airports. […]

Even in its infancy, the program has elicited some protests. […] concerns were raised this week by two of the foremost proponents of the techniques, a former Israeli security official and a behavioral psychologist who developed the system of observing involuntarily muscular reactions to gauge a person’s state of mind. They said in interviews that the agency’s approach puts too little emphasis on the follow-up interview and relies on a behavior-scoring system that is not necessarily applicable to airports.

Read the whole article (registration required):

Which Travelers Have ‘Hostile Intent’? Biometric Device May Have the Answer

A timely Wall Street Journal article (14 August) on Cogito, a system that measures physiological responses of air passengers and decides if they are a mock terrorist with 85% accuracy! Woo!*

At airport security checkpoints in Knoxville, Tenn. this summer, scores of departing passengers were chosen to step behind a curtain, sit in a metallic oval booth and don headphones. With one hand inserted into a sensor that monitors physical responses, the travelers used the other hand to answer questions on a touch screen about their plans. A machine measured biometric responses — blood pressure, pulse and sweat levels — that then were analyzed by software. The idea was to ferret out U.S. officials who were carrying out carefully constructed but make-believe terrorist missions.

The trial of the Israeli-developed system represents an effort by the U.S. Transportation Security Administration to determine whether technology can spot passengers who have “hostile intent.”

[…] The technology isn’t geared toward detecting general nervousness: Mr. Shoval [of SDS Systems Ltd] says terrorists often are trained to be cool and to conceal stress. Unlike a standard lie detector, the technology analyzes a person’s answers not only in relation to his other responses but also those of a broader peer group determined by a range of security considerations. “We can recognize patterns for people with hostile agendas based on research with Palestinians, Israelis, Americans and other nationalities in Israel,” Mr. Shoval says. “We haven’t tried it with Chinese or Iraqis yet.” In theory, the Cogito machine could be customized for specific cultures, and questions could be tailored to intelligence about a specific threat.

The company behind the technology is Suspect Detection Systems Ltd, whose team includes individuals with polygraph and interrogation experience, Mossad veterans and a former special advisor to the Israeli Prime Minister’s Office.

Hat tip to Slashdot for the link.

* The ‘woo’ is sarcastic, by the way.

Lying is exposed by micro-expressions we can’t control

Mark Frank moved up to the University of Buffalo last year to continue the deception research he had been doing at Rutgers. Now Buffalo has issued a press release (5 May) highlighting some of the interesting facets of Frank’s research. Much of Frank’s research continues the pioneering work of Paul Ekman (Frank’s former teacher and ongoing collaborator) on identifying facial microexpressions of emotion:

[…Frank’s] revolutionary research on human facial expressions in situations of high stakes deception debunks myths that have permeated police and security training for decades. His work has come to be recognized by security officials in the U.S. and abroad as very useful tool in the identification and interrogation of terrorism suspects.

[…] “Fleeting facial expressions are expressed by minute and unconscious movements of facial muscles like the frontalis, corregator and risorius,” Frank says, “and these micro-movements, when provoked by underlying emotions, are almost impossible for us to control.”

But Frank doesn’t think that understanding microexpressions are the ‘silver bullet’ for deception detection:

“I want to make it clear that one micro-expression or collection of them is not proof of anything,” Frank says. “They have meaning only in the context of other behavioral cues, and even then are not an indictment of an individual, just very good clues.”


  • Link to press release from Buffalo
  • Link to more on Frank’s work (hosted at Rutgers)
  • Link to New Yorker article by Malcolm Gladwell about facial microexpressions (thank you to the Thinking Meat blog for reminding me of this!)
  • Link to more on facial expressions
  • Link to news item on Mark Frank’s work with TSA

Lying in wait for airborne criminals

Controversial device analyzes passengers’ voices
CNN, Thursday, January 5, 2006

Heightened fears of terrorist attacks have lead to a global beefing up of airport security, but controversial new measures are being developed that could see plane passengers screened by lie detectors. Features like iris and fingerprint scanning are now widely used by airlines, but with technology playing an increased role at frontiers, so-called E-passports containing biometric information about passengers are also becoming more commonplace. […] Now a new walk-through airport lie detector developed by Israeli scientists could throw up yet another layer of security to ensure potential hijackers or contraband smugglers do not gain access to international flights. The GK-1 voice analyzer, created by Israeli firm Nemesysco, requires passengers to don headphones at a console and answer “yes” or “no” into a microphone to questions about their travel plans.

This is a rehash of a story that first appeared on Reuters, November 17, 2005.