Counterterrorism experts have drawn up plans to develop an array of advanced technologies capable of spotting would-be terrorists in a crowd before they have time to strike, reports New Scientist Magazine.

Scientists and engineers have been asked to devise ways of analyzing people’s behavior and physiology from afar, in the hope they may reveal clues about their mental state and perhaps their future intentions.

Under Project Hostile Intent, scientists will aim to build devices that can pick up telltale signs of hostile intent or deception from people’s heart rates, perspiration and tiny shifts in facial expressions.

The project was launched by the Department of Homeland Security (DHS) with a call to security companies and government laboratories for assistance.

According to the prepared timetable, the new devices are expected to be used at a handful of airports, borders and ports of entry by 2012.

The plans describe how systems based on video cameras, laserlight, infrared, audio recordings and eye-tracking technology are expected to scour crowds looking for unusual behavior, with the aim of identifying people who should be approached and quizzed by security staff, according to the magazine.

The project aims to advance a security system already employed by the Transportation Security Administration (TSA) that monitors people for unintentional facial twitches called “micro-expressions” that can suggest someone is lying or trying to conceal information.

Studies by Paul Ekman, a psychologist at the University of California, San Francisco, have revealed that involuntary expressions can often betray someone’s true intentions. For instance, flashing teeth, lowering eyebrows and wrinkling a nose for a fraction of a second while trying to smile all demonstrate the micro-expression for disgust.

A major hurdle will be developing technology that can make correct decisions quickly. “Right now, screeners have typically less than one minute to examine a traveler’s documents and assess whether they are a threat,” Larry Orluskie of the DHS tells New Scientist magazine.

The project is also expected to investigate developing a lie detector-type test that can be used remotely — an advantage because it would not interfere with the flow of a crowd and it could be used without the target’s knowledge.

Experts are skeptical that today’s technology will be able to predict hostile intent accurately enough to be useful. Ekman says a terrorist might confound security measures by showing a range of expressions from fear of being caught to distress at the possibility of dying.

Anthony Richards, a counterterrorism expert at St. Andrews University, Scotland, who has worked on Britain’s ability to preempt a major terrorist attack, agrees that the project faces substantial hurdles.

“There could be all kinds of reasons that might make people behave in certain ways that have nothing to do with terrorism. If you have heightened security and there are a lot of police around, it could be possible that you can feel and look guilty even when you haven’t done anything wrong,” Richards says.