Category Archives: investigator

Lie detection

Lie detection is a hotly debated area of modern day psychology. Although it is not an exact science, there are techniques and methods that allow experts to judge if someone is telling the truth or not. Polygraph tests go some way in detecting lies, but they are not always available or feasible for every case. Instead investigators use a number of observational methods to establish whether someone is lying, including facial expressions and body language.

Micro expressions

It is widely accepted that faces exhibit two messages – what the liar wants to show and what they want to hide. Micro expressions refer to these brief, involuntary facial expressions that reveal their true emotions. This flash of leakage is there and gone in a matter of nanoseconds, so you have to be quick to catch it. Whilst this cannot prove guilt or deception, the behaviour does indicate dishonesty and warrants further investigation.

False expressions

Tied to this notion of micro expressions is the subject of false expressions. These nonverbal behaviours are forced or exaggerated to conceal true emotions, and research has shown that these faked expressions are asymmetrical.

For example, smiling may indicate a false expression when the eye muscles are not used. A genuine smile involves the movement of the outer part of the eye, so no matter how big the grin may be, a lack of eye expression may be the telling sign. If someone is afraid or sad, the absence of forehead expression hints that they are falsifying their emotions.

By studying the symmetry of a suspect’s face, experts may be able to detect a liar from a truthteller.

Body language

Studies have suggested that liars often gesticulate with their hands after they talk. This is because their brain is so preoccupied with making up and remembering a story, meaning that hand gestures that might normally appear before a statement happen afterwards instead.

Fidgeting is a common sign of lying. Twitching, shuffling feet and clasping hands are behaviours that may indicate guilt or deception due to fluctuations in the autonomic nervous system. This system regulates bodily functions, and when people are nervous it may manifest itself in fluctuations that cause itches or tingles in the body.


It’s an exaggerated image we’ve all seen in movies and TV when a suspect is being questioned – sweat dripping from every pore in their body. Whilst it may not be this extreme, it is true that lying suspects sweat more due to automatic nervous system changes. If you notice someone’s forehead or upper lip perspiring, it could be a sign of deception.

To find out more about how we catch liars and get to the truth, get in touch with ICFECI today.