Over the decades the research in body language has gone from the naive to the highly sophisticated... to a point where a proper investigator in body language uses a variety of tools in lie detection as any one piece of evidence could be wrong (for various reasons). [ Learn more about body language basics from Psychology Today]
How to Spot a Liar - From Time MagazineFew things are easier than telling a lie, and few things are harder than spotting one when it's told to us. We've been trying to suss out liars ever since Cain fibbed to God about murdering Abel. While God was not fooled--hearing the blood of Abel crying out from the land--the rest of us do not have such divine lie-detection gifts.
But that doesn't mean we're not trying. In the post-9/11 world, where anyone with a boarding pass and a piece of carry-on is a potential menace, the need is greater than ever for law enforcement's most elusive dream: a simple technique that can expose a liar as dependably as a blood test can identify DNA or a Breathalyzer can nail a drunk. Quietly over the past five years, Department of Defense agencies and the Department of Homeland Security have dramatically stepped up the hunt. Though the exact figures are concealed in the classified "black budget," tens of millions to hundreds of millions of dollars are believed to have been poured into lie-detection techniques as diverse as infrared imagers to study the eyes, scanners to peer into the brain, sensors to spot liars from a distance, and analysts trained to scrutinize the unconscious facial flutters that often accompany a falsehood.
At last they may be getting somewhere. Next month No Lie MRI of San Diego, a beneficiary of some of that federal largesse, will roll out a brain-scan lie-detection service it is marketing to government and industry. Another company, Cephos of Pepperell, Mass., hopes to follow within a few years.
The following is an introduction to the science of lie detection...
Above image represents all the directions your eyes move when processing information.
(Both of the above images are from here.)
1. New emotion detector can see when we're lying
A sophisticated new camera system can detect lies just by watching our faces as we talk, experts say. The computerised system uses a simple video camera, a high-resolution thermal imaging sensor and a suite of algorithms. Researchers say the system could be a powerful aid to security services. It successfully discriminates between truth and lies in about two-thirds of cases, said lead researcher Professor Hassan Ugail from Bradford University. The system, developed by a team from the universities of Bradford and Aberystwyth in conjunction with the UK Border Agency, was unveiled today at the British Science Festival in Bradford. This new approach builds on years of research into how we all unconsciously, involuntarily reveal our emotions in subtle changes of expression and the flow of blood to our skin.
For more than 15 years, Robert Hanssen led a double life. In one life he was a 25-year veteran with the Federal Bureau of Investigation (FBI) who had access to some of the nation's most-classified information. In his other life, he allegedly was spying for the Russian government. Hanssen's deception was finally discovered, and in February 2001 he was arrested and later pled guilty to 15 espionage-related charges. Spies are probably the world's best liars, because they have to be, but most of us practice deception on some level in our daily lives, even if it's just telling a friend that his horrible haircut "doesn't look that bad."
Using the above devices combined with the information of human biology and eye accessing cues (and clever questioning with a video camera present in addition to the heat sensors), lie detection should become pretty accurate. Then some proper evidence, a motive and lie detection results with a variety of independent experts... and you could have an air-tight case for a lie.