Fingerprinting air passengers entering the United States is one counter-terrorism method used today . But the Department of Homeland Security (DHS) has another idea in the works: a behavioural biometrics monitoring system that gauges small changes in a person's body, dubbed the "fidget factor," especially in answer to a question such as "Do you intend to cause harm to America?"

DHS has actually developed a prototype for putting subjects on a monitoring pad next to a battery of remote sensing equipment that can very quickly measure ocular changes, heart and respiration rates and even slight changes in the skin's thermal properties as a way to detect suspicious behaviour. Dr. Starnes Walker, director of the research, science and technology directorate at the DHS, discussed the effort during a keynote address at this week's Biometric Consortium Conference in Tampa.

A film clip of the Future Attribute Screening Technology (FAST) prototype was also shown.

There's no specific timeframe to officially introduce the technology for real world use, said Dr. Sharla Rausch, director of science and technology, human factors, in the behavioral sciences division at DHS, which has the mission of advancing national security and countering terrorism through study and application of social, behavioural and physical sciences, including biometrics.

Rausch, who also spoke about FAST, said the combination of monitoring technologies is aimed at suspicious behaviour detection, and gauging motivation and intent. Some people are very good at hiding their intentions, she said, "but we're trying to develop technologies to give that edge."

Under what has been called Project Hostile Intent, for instance, scientists have been studying "microfacial leakage" for the purposes of "predictive screening" that might be related to a potential bomb, she said. It's all about looking at changes in skin, heartbeat changes, pupil changes. In a lab setting, she said, "there's a correlation between fidgeting and lying," along with "mal intent."

Rausch acknowledges it's necessary to get public feedback before putting a technology like FAST into actual use. "It has to be publicly acceptable," she said.

More sophisticated use of biometrics rapidly accelerated in the US after the terrorist attacks of 9/11. But fingerprinting of international passengers entering the US, controversial when it began, remains an unpleasant experience, especially since it reminds many of a criminal  processing procedure. The US is looking at adding less invasive biometrics, such as a simple iris or facial scan.

While not addressing the topic of FAST technologies specifically, University of Pittsburgh Assistant Professor Lisa Nelson pointed out in a presentation she gave that her study of biometrics and the public views about it reveals tolerance and support when it comes to government use of biometrics to protect public safety.

Although privacy advocacy groups are supposed to represent the public, Nelson said her studies based on focus groups show that "there are differences between public perception and how privacy advocates were framing the issues," with the larger public apparently far more willing than privacy advocacy groups to accept biometrics when it's used for purposes of protecting against terrorism or identity theft.