From little white lies to nation-destroying omissions, lying has been around as long as the truth. And while lying has a rich history, the vast majority of humanity, almost all of the time, tells the truth. And why not? It is far easier, creates an atmosphere of trust, and facilitates a stable society. But every now and again, you get the sneaking suspicion that the person across from you isn't giving it to you straight.

Everyone wants to know how to catch liars in the act...in fact, while this article has some great tips, you can find even more information in Bust Liars: Become a Human Lie Detector. This book will tell you everything you need to know about picking up on those subtle hints liars can't help but display.

So how do you tell if you're being lied to? Before we cover that, we have to ask two important questions.

The first question is: Do you really want to know? Some people willingly blind themselves and accept a lie as fact solely because the truth might be too painful to handle.

On the other hand, some people are so desperate to believe that the painful truth is a lie that they will see “signs of lying” where none exist.

The first step to discovering a lie, then, is to be aware of your personal feelings about the subject. In other words, what is your involvement in this possible lie?

The second question is: Why would this person lie to you? What is at stake here? Maybe he is afraid of being punished, or of the loss of the ability to obtain what he desires (for instance, your business), or, ironically, he is afraid he will lose your trust.

In order to really be accurate in spotting a lie, you must be aware of the other person's motivations for lying to you, including what you might do to him if you knew the truth.

An example of this is a child lying to a parent to avoid being grounded: He is desperately avoiding the punishment he is certain the truth would bring. The parent, being aware of this, is in a better position to gauge the child's lie.

So, you want to know, you're certain he has a reason and you've got the feeling that he is hiding the truth? Let's test that theory...with science!

Know how he talks normally. The first step to reading a liar's body language is to know his normal, everyday conversational habits. This is referred to as someone's “baseline” behavior – normal eye, hand and body movements during a pleasant conversation in which there is no pressure or lying. This will allow you to detect variations when the lie occurs, without mistaking a naturally awkward or shy person for a chronic liar. Notice how stress influences his patterns. It is notoriously difficult to tell the difference between a person who has been put on the spot (that is, under stress and pressure), and an out-and-out liar. This is because most of the tell-tale signs of lying are based around the fact that telling a lie is a stressful event on the body and mind – it seems humans are not built for distorting the truth, and forcing that situation has recognizable repercussions. Look for the signs. This is a list of the most common “tells” that people have while attempting to lie. Again, note that most of these also occur when someone is feeling stressed by the conversation. Little to no body movement. People will sometimes “freeze,” not quite facing the other person, and will move as little as possible during the lie. Alternatively, some people will fight this by being overly dramatic, moving the body much more than normal to try and “sell” the lie.

No eye contact. A lot of information is conveyed through eye contact, and most people have an extremely hard time lying to someone while looking directly into his eyes. Sometimes this will only occur at the moment of the lie, a brief glance at the floor or to the right. Again, some will try to sell the lie by making and maintaining eye contact fiercely, much more so than usual.

Stress gestures (rapid blinking, scratching, itching, swallowing, fidgeting, etc.) . If discovered, a deception carries much greater risk of punishment than simply telling the truth, and people understand this. This uncomfortable situation will make them uncomfortable, and they will act accordingly.

Looking up to the right. Looking up and to the right stimulates the part of the brain associated with imagination (that is, making things up), whereas looking up and to the left stimulates the part of the brain associated with recalling memories (that is, telling the truth).

Touching the nose and covering the face/mouth. Habits from childhood, these gestures are a subconscious attempt to “cover up” the lie, and put distance between the liar and you.

Rise in vocal pitch. Another product of stress, the liar's voice will get higher and squeaky. This should be noticeable if you are familiar with his normal speaking voice.

Wide-eyed, innocent look. Another product of childhood fibs, based on the “who, me?” fake innocence usually associated with a kid denying he has his hand in the cookie jar while it is still in there.

A noticeable pause in speaking. Most people lack the ability to come up with a plausible fiction in an instant, so they have to take a moment to think something up. This results in a pause, usually right before the lie itself, while they desperately reach for something other than the truth. Careful questioning will reveal variations in their story, as a consistent fiction is hard to remember, whereas actual events are usually easy to recall. Lying by omission. Sometimes a lie will happen by not speaking – that is, the liar omits an important piece of information from an otherwise truthful statement. However, this omission will, in the mind of the liar, poison the “truthful” statement, thus rendering it a lie. The above signs will still be present, with the addition of more obvious signs after he has finished talking. (An example: After talking in a relatively truthful manner, he falls silent and immediately looks away, covering his mouth and fidgeting.) Ask. A risky maneuver, as a person who is telling the truth may be horribly offended. Sometimes, however, a liar will come clean if given the chance to, as he realizes that continuing to lie when you know he's doing so would be far worse than just admitting the lie. Trust your intuition. Notice I say “intuition” and not “desire.” Most people have a pretty decent “lie detector” built in, and if you trust it, it can usually point the way. However, some people may want to believe they are being lied to, and they mistake this desire for “a gut feeling.” So before you start accusing anyone of a lie, make sure you're not trying to project your desire on an innocent person.

Using the above steps, you should be able to determine the difference between a lie and the truth to a much more accurate degree. And while we may not have an answer to how to define truth for certain, we will at least be able to tell if the other person feels like he is lying...and if it feels like a lie, it probably is.

Good luck!