NEW YORK — A few weeks ago, customs inspectors at John F. Kennedy Airport were carefully watching hundreds of passengers coming off a flight from South America, looking for telltale body language that would indicate exceptional nervousness.
They quickly focused on one man because his lips were so chapped and dry they were almost white, and "his carotid artery was jumping out of his neck," says supervising inspector Vincent Digilio.
After questioning the man, Digilio and another inspector discovered that he had paid cash for a business-class ticket, even though he was a low-paid service worker. They X-rayed him and found he had swallowed several bags of heroin pellets.
Body language used to be something teenagers studied on first dates. But in the wake of Sept. 11, the science of spotting nervous or threatening behavior is gaining newfound respect among law-enforcement officials, particularly as a way to prevent terrorism.
Since the terror attacks, the Federal Bureau of Investigation has started teaching nonverbal behavior analysis to all new recruits. At the U.S. Customs Service, which has been asking agents to step up their use of "behavior profiling" since 1999, in part to combat accusations of racial profiling, all agents now are being required to watch a video teaching them techniques for studying body language. Rather than selecting people to be interrogated based on what they look like, Customs agents have been trained to watch what they do and ask pointed questions to increase 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. For example, fleeting smiles may indicate "duping delight," when a suspect believes he has put something over on a questioner.
"Terrorists behave differently than legitimate people," says Rafi Ron, an Israeli security consultant, who contends that well-trained body-language profilers might have spotted and questioned some of the Sept. 11 hijackers "by very basic behavior pattern recognition work."
Ron is now overseeing a project at Boston's Logan Airport to train more than than 200 Massachusetts state troopers to watch for things such as darting eyes and hand tremors and to conduct rapid-fire questioning to find inconsistent stories. Other airports could soon follow. The federal Transportation Security Administration, which is taking control of airport security, has requested that some federal passenger screeners receive training on spotting suspicious behavior, according to security consultants vying for the work.
To augment human spotters, some security experts envision enlisting computers. Systems under development could watch security cameras and spot people running or or lurking in deserted corridors. A New York company founded by Israeli intelligence veterans, Secant Aviation Security Inc., is developing software that automates behavior analysis through such tools as hidden voice-stress sensors. They would be set up at various airport locations such as check-in desks. A unit of SRI International Inc., Sarnoff Corp., developed a program that will show the path that every individual follows as he walks through a building.
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 observation of behavior and body language in the 1970s. It also hasn't had a hijacking in more than 30 years.
Americans are likely to find themselves subjected to a new level of public 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.
The shift raises the specter of anxious travelers coming under suspicion when they're just nervous about flying. So "a very high degree of training" of those doing the body-language monitoring is "the only way to make a system like this work," says David Harris, a law professor at the University of Toledo College of Law.
Civil libertarians worry that authorizing police to act based on observation of legal but suspicious activities will give them license to harass people who are minding their own business. "Police have said 'let us use our judgment,' but we as a freedom-loving society have said 'that's way too much discretion to give to law enforcement,' " says Frederick Lawrence, a Boston University law professor. "We may not have to wait too long for that first (privacy) lawsuit."
Some dispute the idea of accurate behavior analysis. Arvid Kappas, a psychology lecturer at the University of Hull in Great Britain and student of facial-activity research, contends that analysis of nonverbal behavior isn't much more reliable than handwriting analysis or "reading bumps on people's skulls."
People can be trained to act normally under even sharp questioning. Drug couriers have been known to use tranquilizers to avoid acting nervous. "As we develop these techniques and they become publicized, the enemy will become aware of it and will develop countermeasures," says Jack Devine, a former Central Intelligence Agency official who now heads a New York investigative firm called the Arkin Group. "This is an age-old cycle."
Customs officials say their experience shows that behavior profiling can work. They overhauled their tactics after some Jamaican and Colombian women were forced to take laxatives in unsuccessful efforts to discover drugs. After Customs placed more emphasis on looking for suspicious behavior and one-on-one questioning, the "hit rate" at which they found drugs during passenger searches reached 22.5 percent, compared with 4.2 percent 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 odd. He fiddled with the car's center console and failed to make eye contact as she spoke to him. After she asked him to leave his car, Ressam was found to be carrying a stack of bomb components. He later confessed to planning to disrupt the millennium celebrations in Los Angeles.
"It was a wake-up call for us at Customs," Dean says. "When I look at everybody now, I leave open the possibility that they could be a terrorist. That's the way every inspector is being trained now."
Although defendants sometimes argue that searches based on behavior profiling are invalid, courts generally uphold them, based on a 1968 Supreme Court ruling. In that case, a Cleveland police detective stopped and searched several youths walking back and forth outside a store "because they didn't look right to me at the time." When he approached them to ask their names, they "mumbled something." 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.
The term body language entered the popular vocabulary a quarter of a century ago after research on benign behavior: courting rituals. Julius Fast wrote a book called "Body Language" that became a best-seller. But "we've come a long way from 1975," says Joe Navarro, an FBI special agent who lectures on the subject. "We believe the study of nonverbal behavior has progressed to such a degree that in capable hands, it is now more accurate than lie-detector tests."
Much of the science was developed by Paul Ekman, a University of California at San Francisco psychologist, who published in 1978 what he called the Facial Action Coding System, or FACS. That standardized system has made it possible for trained researchers around the world to analyze expressions in the same way.
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. Our eyes widen with excitement or fear. Our nostrils flare when we're aroused, and blood flow increases, reddening our skin when we're preparing for a fight, whether it's of a physical or mental nature. It is hard to suppress these expressions, Ekman maintains, because they emanate from areas of the brain that control many of the involuntary muscles.
Ekman particularly focuses on what he calls "micro-expressions," such as a momentary downward twist of one end of the mouth demonstrating contempt, or a quickly suppressed smile. He says such fleeting expressions take less than 0.2 seconds but involuntarily reveal the subjects' true emotion. Ekman says that observers can be trained to spot these micro-expressions and tell if subjects are lying or hiding information.
While most of his work has been academic, he has trained Secret Service agents, Israeli bodyguards and Scotland Yard detectives in scanning crowds for people who might be dangerous. Last month, Ekman says, he received a contract from the Defense Department to analyze videotapes of 250 convicted criminals and their accomplices, including some involved in terrorism. He'll try to identify facial expressions that indicate disdain.
"These people have nothing but contempt for the people they are about to prey on," Ekman says, adding that he'll "be looking to detect any signs of such feelings and sentiments."
Schools that train law-enforcement officers have borrowed heavily from facial and body-language studies ever since Ekman's initial work. Instructional materials from John E. Reid & Associates Inc., Chicago, which operates one of the oldest interview and interrogation training programs, say an untruthful person is "more likely to engage in grooming gestures or major body movements as tension relievers when answering key questions." Postures that suggest someone might be lying include slouching, turning away, or making erratic posture changes. Avoiding eye contact often suggests untruthfulness, although, for example, Asian women often avoid eye contact with men as a cultural norm.
It was body language that helped the FBI's Navarro solve the case of a missing child in August 1999. A 22-year-old woman had FBI agents and local sheriff deputies looking for her 6-month-old son, who she said had been kidnapped in the parking lot of a Wal-Mart in Tampa, Fla. As the sobbing woman, Christa Decker, told her story inside police headquarters, Navarro observed through a one-way mirror.
Following the interview, Navarro told sheriff's 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 gesticulate with their arms and face, they're expressive," he says. Liars are more interested in keeping their facts straight — an effort that forces them to be calm and composed. Decker was called back for a second interview, during which she confessed that she had suffocated the child by putting him inside a plastic garbage bag.
This spring, in a symposium for Florida police at St. Leo College, Mr. Navarro demonstrated the techniques. He randomly picked police officer Michael Kitts and asked him to pretend he had just murdered someone, keeping in mind the weapon he used. Then, staring him in the eye, Mr. Navarro recited a list of possible weapons: machete, gun, bat, knife, stick, boulder, rock. Mr. Kitts remained stone-faced.
"You chose a knife didn't you?" Mr. Navarro asked.
"Yes," says Mr. Kitts.
Though Mr. Kitts had remained poker-faced, his blink-rate increased and he swallowed hard at the mention of a knife, Mr. Navarro says.
Behavior-profiling techniques have also become more elaborate outside of law enforcement. In Las Vegas casinos, where video cameras are everywhere, behavior analysis sometimes pinpoints a person about to commit a crime.
In late July, surveillance officers at the Venetian spotted a pony-tailed man who walked in at 2:13 a.m. and grabbed a stack of plastic coin-cups but didn't go to the slot machines. "Why would he get cups if he isn't playing?" Daniel Eitnier, the surveillance director, remembers thinking. From that moment, "this guy looks like he's got a purpose to be here but it's not gambling." The man confirmed the suspicions by "rubbernecking": looking right and left and peering at guards and the ceiling instead of at other gamblers and machines.
At 2:16 a.m., the surveillance officers followed him to a slot machine where a partner had previously broken the lock. The man shoved his hand down into the machine and drew out fistfuls of coins. A few seconds later, he got up to leave and security guards tackled him.
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 some experts hope automation will come in.
The CIA has commissioned two research centers, the Salk Institute and Carnegie Mellon University's Robotics Institute, to attempt to teach computers to watch for detailed facial-language clues. Both prototypes have been completed and are being reviewed for accuracy and potential applications.
Terrence Sejnowski, a researcher at Salk Institute in La Jolla, Calif., says analyzing a minute of an interview can take a trained observer an hour, but a computer might handle the process in real time. Dr. Sejnowski is applying for grants to turn his research prototype into a commercial system to observe psychiatric patients. He is less eager to see it used in security, fearing it "could be misused."
Secant Aviation aims to computerize the Israeli airline's method of passenger screening. The New York company is creating software 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 technology, 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, it might trigger an alert to security people to pull her aside for questioning.
Sarnoff, which is in Princeton, N.J., has developed computer programs that take information from hundreds of cameras around a building and create "tracks" showing where each person has been. The firm says it could be useful in airports to spot people slipping in through exit doors.