Chicago ? A would-be terrorist tries to board a plane, bent on mass murder. As he walks through a security checkpoint, fidgeting and glancing around, a network of high-tech machines analyzes his body language and reads his mind.

Screeners pull him aside.

Tragedy is averted.

As far-fetched as that sounds, systems that aim to get inside an evildoer’s head are among the proposals floated by security experts thinking beyond the X-ray machines and metal detectors used on millions of passengers and bags each year.

On Thursday, in the wake of the Christmas Day bombing attempt over Detroit, President Barack Obama called on Homeland Security and the Energy Department to develop better screening technology.

Some of the more unusual ideas are already being tested. Some aren’t being given any serious consideration. Many raise troubling questions about civil liberties. All are costly.

“Regulators need to accept that the current approach is outdated,” said Philip Baum, editor of the London-based magazine Aviation Security International. “It may have responded to the threats of the 1960s, but it doesn’t respond to the threats of the 21st century.”

Here’s a look at some of the ideas that could shape the future of airline security:

Mind readers

The aim of one company that blends high technology and behavioral psychology is hinted at in its name, WeCU — as in “We See You.”

The system that Israeli-based WeCU Technologies has devised and is testing in Israel projects images onto airport screens, such as symbols associated with a certain terrorist group or some other image only a would-be terrorist would recognize, company CEO Ehud Givon said.

The logic is that people can’t help reacting, even if only subtly, to familiar images that suddenly appear in unfamiliar places. If you strolled through an airport and saw a picture of your mother, Givon explained, you couldn’t help but respond.

The reaction could be a darting of the eyes, an increased heartbeat, a nervous twitch or faster breathing, he said.

If the sensors picked up a suspicious reaction, the traveler could be pulled out of line for further screening.

Lie detectors

One system being studied by Homeland Security is called the Future Attribute Screening Technology, or FAST, and works like a souped-up polygraph.

It would subject people pulled aside for additional screening to a battery of tests, including scans of facial movements and pupil dilation, for signs of deception. Small platforms similar to the balancing boards used in the Nintendo Wii would help detect fidgeting.

The Israeli model

Some say the U.S. should take a page from Israel’s book on security.

At Israeli airports, widely considered the most secure in the world, travelers are subjected to probing personal questions as screeners look them straight in the eye for signs of deception. Searches are meticulous, with screeners often scrutinizing every item in a bag, unfolding socks, squeezing toothpaste and flipping through books.

Profiling

Some argue that policies against profiling undermine security.

Baum, who is also managing director of Green Light Limited, a London-based aviation security company, agrees profiling based on race and religion is counterproductive and should be avoided. But he argues that a reluctance to distinguish travelers on other grounds — such as their general appearance or their mannerisms — is not only foolhardy but dangerous.

“We need to use the human brain — which is the best technology of them all,” he said.