ARCHIVE :: OCTOBER 2002 :: LAW & POLITICS

The Telltale Twitch
Law-Enforcement Officials Zero In on Body Language to Sniff Out Terrorists

By Ann Davis, Joseph Pereira and William M. Bulkeley
Staff Reporters of The Wall Street Journal

Body language used to be something young lovers studied on first dates. But in the wake of the Sept. 11 attacks, the science of spotting nervous or threatening behavior is gaining new respect among law-enforcement officials.

Click image above to see examples of behavior profiling.

Since the attacks, the FBI has started teaching nonverbal-behavior analysis to all new recruits. At the Customs Service, which targets smugglers, rather than selecting people to be interrogated based on what they look like, agents have been trained to watch what they do and ask pointed questions to raise their stress levels.

And during interrogation, instead of just listening for inconsistencies in what is said, agents are being taught to look for minute physical reactions on the faces of people being questioned, like fleeting smiles that may indicate when a suspect believes he has fooled a questioner.

"Terrorists behave differently than legitimate people," says Rafi Ron, a security consultant, who contends that trained body-language profilers might have spotted and questioned some of the 9/11 hijackers. Mr. Ron is overseeing a project at Boston's Logan Airport to train more than 200 state troopers to watch for things such as darting eyes and hand tremors and to conduct rapid-fire questioning to find inconsistent stories.

To augment human spotters, security experts envision enlisting computers. A company founded by Israeli intelligence veterans, Secant Aviation Security, is developing software that automates behavior analysis through such tools as hidden voice-stress sensors at airports.

Safe or Sorry?

Security experts say the result will be safer airports and public places. Many point to the Israeli airline El Al's reliance on behavior surveillance. It pioneered such techniques in the 1970s. It also hasn't had a hijacking in more than 30 years.

But Americans are likely to be subjected to a new level of scrutiny. It may become normal to be stared at or questioned by officials looking for nervous or distracted behavior, and secretly examined by video and voice monitors. That raises the prospect of travelers coming under suspicion when they're just nervous about flying. Civil libertarians worry that authorizing police to act based on observation of legal but suspicious actions will give them license to harass people who are doing nothing wrong.

Some dispute the accuracy of behavior analysis. People can be trained to act normally under even sharp questioning. "As we develop these techniques and they become publicized, the enemy will become aware of it and will develop countermeasures," says an ex-CIA official.

But Customs officials say their experience shows behavior profiling can work. After they started placing more emphasis on spotting suspicious behavior and one-on-one questioning, the "hit rate" for finding drugs during passenger searches rose to 22.5%, from 4.2% in 1998.

Body language and behavior led to one prominent terrorism-related arrest. In late 1999, U.S. Customs inspector Diana Dean was checking cars coming off a ferry in Port Angeles, Wash., when she noticed Ahmed Ressam acting oddly. He fiddled with the car's console and failed to make eye contact with her. After she asked him to leave his car, Mr. Ressam was found to be carrying a stack of bomb components. He later confessed to planning to disrupt the millennium celebrations in Los Angeles.

Courts have generally upheld searches based on behavior profiling, drawing on a 1968 Supreme Court ruling. In that case, a Cleveland detective stopped and searched several youths walking outside a store "because they didn't look right to me." The youths, who proved to be armed and planning a robbery, fought the arrests as based on an unreasonable search, but the court said it was justified.

Early research on body language began a quarter century ago, but "we've come a long way," says Joe Navarro, an FBI special agent. "The study of nonverbal behavior has progressed to such a degree that in capable hands, it is now more accurate than lie-detector tests."

One of the pioneers of the science is Paul Ekman, a California psychologist who developed a standardized system for analyzing facial expressions. Dr. Ekman says the brains of all people are similarly wired to the muscles under the skin of the face. Our lips get thinner when we're angry. Our blink rate increases when we're nervous. It is hard to suppress these expressions, Dr. Ekman says, because they emanate from areas of the brain that control the involuntary muscles. Dr. Ekman says certain "micro-expressions"-such as a momentary curl of the mouth demonstrating contempt, or a quickly suppressed smile-involuntarily reveal the subjects' true emotion.

It was body language that helped Mr. Navarro solve the case of a missing child in August 1999. A woman had FBI agents and local police looking for her infant son, who she said had been kidnapped from a parking lot in Tampa.

Following the interview, Mr. Navarro told investigators that he didn't believe her story-her demeanor was too subdued. "When people tell the truth, they make every effort to ensure that you understand them. They're expressive," he says. Liars are more interested in keeping their facts straight-an effort that forces them to be calm and composed. In a second interview, the woman confessed that she had suffocated the child herself.

Faces in the Crowd

For terrorism experts, the challenge remains figuring out how such techniques can be used to survey large crowds instead of just a suspect in an interrogation session. That is where automation comes in.

The CIA has commissioned two research centers to attempt to teach computers to watch for detailed facial-language clues. Meanwhile, Secant Aviation is creating software that it says would mirror the "El Al protocol" by helping analyze how large numbers of people behave as they go through an airport. It would automate much of the analysis, using hidden surveillance tools, and allow screeners to check off any suspicious behavior they see.

The idea is for the computer to collect data on passengers at various points, from curbside check-in to flight gates. For example, baggage handlers might flag for further observation a woman wearing sloppy clothes but checking Louis Vuitton bags. If the system also detected nervousness in her voice when she went through security, and if other risk factors were present in her background, she might be pulled aside for questioning.