Many human relationships run on trust. How do you know if that trust has been broken? Can you handle the truth, or is it better to live in the dark? Most people would probably prefer to be in the know, regardless of how upsetting it might be.

If you don't have incontrovertible personal knowledge of the facts, it can sometimes be difficult to tell whether or not someone is lying to you. The website Blifaloo has an interesting behavioral article: How to Detect Lies. They reveal some visual cues that show you someone might be less than truthful.

We'll discuss a few, and what you can do with them, after the break.

Some of the physical and verbal signs that someone may be fibbing:

• Avoidance of eye contact
• Smiles that mostly involve the mouth and fail to reach the eyes
• Over-explanation
• Eagerness to change the subject of conversation
• A number of other signs, listed in the article

There's a major problem with all this, though, one even mentioned by its author: the information isn't useful with regard to every person in every situation.

Some people -- shy people, people with low self-esteem, etc. -- rarely, if ever, make eye contact. And there are a host of reasons, other than the fear of being caught in a lie, why someone might be nervous in a given situation. Therefore, the information is only useful when compared to the person's usual behavior.

You'll need to decide whether or not it's worth it to you to confront a suspected liar, if there's a risk that you might be wrong. There's a difference between a cheating spouse or substance-abusing child and someone who is politely and falsely claiming to love the gift you gave them. (In the latter case, it might be better to discreetly provide a receipt for the item, or try giving a gift card next year.)

Also, watch out: articles like this often just serve to teach habitual liars to become better ones.