Essentially, we lie to avoid pain or anticipate pleasure.

Men lie differently than women.
Indeed, there are many ways to misrepresent the truth. Part of the problem is that not everyone agrees on the definition of lying. To complicate matters, people in most modern societies have learned to identify different shades of truth. Lying by omission, for example, is a form of passive deceit because a person is withholding information or not volunteering the truth. It's interesting to note that the Fifth Amendment allows someone to refuse comment if such testimony will incriminate him or her, which means that the law allows one to lie by omission. Plagiarism is another form of lying. Plagiarism is a form of “literary theft,” of which I would be guilty, if I didn't tell you that I copied that phrase from the Merriam-Webster dictionary.

Some lying generally is considered harmless. A white lie, for example, is a harmless fib that is meant to be tactful or polite. You have told a white lie if your wife proudly asks what you think of her new, ugly dress and you say, “I really like your new dress, honey.” It is said that a white lie may set the stage for lies of darker hues. Just after complimenting your wife on the ugly dress, she might say, “I'm glad you like the style. These dresses are on sale at the mall. Do you mind if I pick up two more in different colors?” Defensive lying is to deceive another person because the other person is trying to take advantage of you. If a mugger demands your wallet, you might lie by telling him that you don't have any money. (You also can use this response if your wife asks about buying more ugly dresses.) If a car mechanic quotes you $750 to replace a water pump, you might tell him that the place across town will do the job for $650, even if you don't know this to be true.

People lie for two basic reasons. Most people avoid the truth because they anticipate pleasure or they want to avoid pain. When it comes to lying, the anticipation of pleasure usually involves a selfish agenda. Thousands of us lie for purposes of self-interest and self-promotion, such as when we lie on a job résumé. Some people lie because they feel if they tell the truth, they won't get what they want. The avoidance of pain or discomfort often causes people to lie. People often lie because they fear punishment. If someone frequently fears punishment, lying may become a habit, which is lying by reflex. Many people lie to avoid awkward situations or interpersonal conflict. We sometimes lie to ensure privacy such as when a telemarketer calls during dinner.

Men lie differently than women. Research suggests that certain types of lies are idiosyncratic with regard to gender. Men, for example, are more likely than women to engage in self-oriented lies to gain personal advantage or make a positive impression on others. Women, on the other hand, tend to use lies to protect a third party.

Use baseline behavior to judge when someone is lying. Generally speaking, the less someone knows you, the more likely that person may lie. Strangers are more likely to get away with lying because you don't know their baseline behavior. Baseline behavior is how the person acts when he or she isn't lying. Liars usually score high in social skills. Introverts tend to feel more comfortable telling the truth. The most effective liars are those who get a lot of practice. Beware of sales people who use high-pressure tactics such as hurrying your decision. According to author Paul Ekman, author of Telling Lies: Clues to Deceit in the Marketplace, Politics and Marriage, we should beware of stories with too many details, especially details that are unverifiable. Stories that lack details should also ring alarms. Pay special attention to people whose verbal cues do not match their non-verbal cues. Watch for inappropriate verbal content and unusual displays of emotion.

In summary, it pays to be smart and ask questions. Don't be shy about probing for more details. Persist in finding the true source of the information and then try to find an objective person that will corroborate what you've learned. It's best to be a little cynical and develop an affinity for proof. No single source of information is completely infallible. Most lies can be fixed through apology, forgiveness, retribution and the passage of time. The main idea is to not to be involved with lying in the first place.