As the 10th anniversary of the 9/11 terrorist attacks approaches, the Transportation Security Administration (TSA) is experimenting with a plan to supplement high-tech screening measures with what might be considered a more intuitive yet rational strategy. The experiment, implemented last month in Terminal A at Logan Airport, could be called a “No Lie Zone.” On a 60-day trial basis, passengers are to be screened for hints of deception as an indicator of risk.
For periods of four hours every day, about one dozen so-called “Behavior Detection Officers” interview all passengers as they move from the boarding pass identification checkpoint to the electronic body scanners. The one-minute interviews represent a shift from the often-criticized “one search fits all” practices that indiscriminately subject everyone from young children to VIPs to random searches.
Uniformed and plainclothes Behavior Detection Officers have already been on the job for several years at many of the over 400 airports across the nation overseen by the TSA. They are tasked with being on the lookout for passengers who seem to be acting suspiciously. When they find one, the passenger is subjected to a more intensive screening and questioning.
But the new Logan Airport program amounts to a more systematic approach, very similar to profiling; although, considering the sensitivity of the term, no one at TSA is quite calling it that. The TSA says it is modeled on the interactive airport screening methods used in Israel.
Evidence-based selective screening is more productive than random searches, claims George Naccara, director of TSA operations in Boston. "Not only will it strengthen the effectiveness and efficiency of airport security," said Naccara, "but it will improve the experience for passengers.”
The specially-trained TSA officers take a studied casual approach to the interviews of virtually every passenger passing through the security checkpoint. With a friendly smile, they ask such questions as: “Where are you from?” or “Where are you headed?” and then “What is the purpose of your trip?”
Should the passenger display multiple signs of nervousness or inconsistencies in responses, he or she may be questioned further. If concerns persist, then the suspicious oassenger may be subjected to additional screening and possibly a background check through law enforcement. As of this writing, the tactic has resulted in two arrests. But both were related to illegal immigration, not terrorism.
Aware of the civil liberties concerns, I took some time to observe the observers (with their knowledge). From my perspective, there was minimal infringement on privacy, and no one seemed particularly annoyed by the increased scrutiny. Nevertheless, while the screeners’ questions were benign, I wondered whether they were beneficial.
Statistical profiling based on various demographic attributes is easy to implement, but also easy to beat. In contrast, behavioral profiling based on suspicious actions or statements can be effective, but is difficult to do well.
With sufficient time and attention, well-trained observers may be able to detect micro-expressions of deceitfulness and potential danger, the kind of work portrayed in the popular FOX TV program “Lie to Me.”
But even Paul Ekman, the psychologist after whom the show’s skilled deception detector was based, has noted, according to an article in the Los Angeles Times, the challenges of applying these tools widely in crowded airport settings. Moreover, a Government Accountability Office (GAO) report published last year highlighted the need for scientific validation studies on the use of behavior detection methods for identifying terrorist threats.
Behavior detection may have worked successfully in Israel, which has one major international airport serving about a million passengers monthly. However, the cost and complexity of interview-based screening of the millions who pass through our nation’s major airports on a daily basis would likely be staggering.
Beyond the issue of scale, the most significant hurdle to evaluating the Logan experiment is in defining success. Should there be no major security breaches, as there rarely are under normal operations, how would we know if the practice had accomplished its objective of shielding us from terrorist activity?
Ultimately, the problem for any behavioral screening procedure, no matter how capable the observers and how thorough the inquiries, surrounds what is known as the “low base rate fallacy.” How can we find the very few dangerous needles in a massive haystack of suspicion?
Generally, it is nearly impossible to identify rare events with any degree of reliability, even if the tools are highly accurate. There are many travelers who may appear anxious, hurried and suspicions, but extremely few who actually pose a threat. The lower we place the threshold for further investigation, the more time and resources we waste working through the pile of false positives.
Notwithstanding the GAO report from last year, TSA has continued to examine the value of its behavior detection strategies. Next Friday, Rep. Bill Keating, Chair of the House Homeland Security Subcommittee on Oversight, Investigation and Management, will be holding a public hearing at Logan to review matters related to airport security. Reportedly, TSA will offer testimony concerning a recent valildation study indicating that screening guided by observations of behavior faired significantly better than random selection.
Of course, time will tell whether behavior detection can work at a large scale. And even if implemented selectively at only the nation’s busiest airports, system-wide vulnerability is predicated on the least secure among the hundreds of airports that are under federal supervision. As happened on 9/11, a terrorist can gain access to the secure areas of all airports by penetrating the security checkpoint at any one. That is, once through security at any U.S. airport, a passenger can travel to others around the country without re-screening.
Whatever their value, the constantly changing security policies implemented at U.S. airports over the past decade have lent new meaning to the “lines” in “airlines.” Of course, various security-related hassles would be tolerable if they made us safer.
However, security experts and politicians have questioned whether all the rules and prohibitions imposed upon the traveling public indeed protect us from the threat of a terrorist assault. Among the harshest critics is security specialist Bruce Schneier, who has called TSA’s airport strategies “Security Theater,” referring to procedures that make travelers feel secure without improving security.
And Utah Rep. Jason Chaffetz, who chairs the House Subcommittee on National Security, was decidedly blunt in his assessment, characterizing the current state of airport security as “a mess.”
Although the criticism may be somewhat overstated, some past security strategies -- such as the not-so-secretive “S” on a passenger’s boarding passes to indicate pre-selection for a checkpoint search, or the recently abandoned color-coded threat levels -- hardly inspired confidence.
While behavioral profiling can be useful, security may best be achieved by enhancing covert methods, such as surveillance, and by strengthening investigative intelligence. Screening of all checked luggage is worthwhile. So are cockpit dividers and air marshals. Electronic body scanners may be a deterrent, but let’s end the time-consuming charade of removing coats and shoes and of confiscating toothpaste and nail clippers.
Until airport screeners can rely on some broad-based passenger-risk classification system, we should strive to minimize the visible inconveniences imposed upon the flying public. Terrorism involves the threat of force to achieve an objective. By curtailing our freedoms and inconveniencing ourselves any more than is necessary, we play right into the hands of our enemies.
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Note: An earlier version of this blog appeared in The Crime Report , the nation's most comprehensive daily source of criminal justice news and analysis.
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