Being able to read "nonverbal communication"-body language-is essential in business dealings. Problem is, we usually interpret a smile or lack of eye contact through an emotional screen, not a scientific one. Sometimes a smile is a sign of happiness-and sometimes it's a flash of contempt. Here is what modern communications science has to say about the myths of body language.

Most people call it "body language"-the clues to the meaning and intent of communication from others that we get from gesture, facial expression, posture-everything that isn't spoken. The experts call it "nonverbal communication," but it amounts to the same thing: a second source of human communication that is often more reliable or essential to understanding what is really going on than the words themselves.

Or is it? Accurate knowledge of body language is essential for success in interpersonal relations, whether in the business world or in personal life. However, much of our understanding is instinctive-and a good deal of it is wrong, according to modern communications research. What follows are some of the hardier myths, and the reality behind them.

1. A liar can't look you straight in the eye. There is a persistent belief that people with shifty eyes are probably lying. As Paul Ekman says in his classic work, Telling Lies: Clues to Deceit in the Marketplace, Politics, and Marriage, "When we asked people how they would tell if someone were lying, squirming and shifty eyes were the winners. [But] clues that everyone knows about, that involve behavior that can be readily inhibited, won't be very reliable if the stakes are high and the liar does not want to be caught."

Ekman goes on to argue against attributing too much meaning to such behavior for two reasons. First of all, although this kind of nonverbal communication most reliably signals the presence of some kind of emotion, that emotion may or may not mean that someone is lying. Nervousness can, for example, manifest itself as shifty eyes. But there are many reasons for nervousness. To understand what the behavior means, you still have to interpret the emotion.

Second, Ekman has found that one group in particular excels at making eye contact that appears very sincere: pathological liars. Hence, it is not safe to rely on eye contact as a measure of sincerity or truthfulness.

2. When meeting someone, the more eye contact, the better. This long-held belief is the inverse of the idea that shifty-eyed people are liars. The result is an unfortunate tendency for people making initial contact-as in a job interview, for example-to stare fixedly at the other human. This behavior is just as likely to make the interviewer uncomfortable as not. Most of us are comfortable with eye contact lasting a few seconds, but any eye contact that persists longer than that can make us nervous. We assume that there is something else going on-an attempt to initiate flirtatious behavior, perhaps. Indeed, studies on flirting show that prolonged eye contact is an early step in the process.

3. Putting your hands behind your back is a power gesture. For years presentation coaches have taught people to put their hands behind their backs in what is sometimes called the "Prince Charles" stance, in the mistaken belief that the heir to the British throne is a good model for strong body language. Since he's a prince, the thinking goes, and he stands that way a lot, it must be powerful.

Actually, the research shows that most people find the gesture untrustworthy-if we can't see what your hands are doing, we're suspicious. So if your goal is to increase trust in any given situation, don't put your hands behind your back.

4. "Steepling" your fingers shows that you're intellectual. Again, this technique is one that has been taught by many speech coaches. A good deal of research over the years correlates hand gestures toward the lower part of the face with thinking-stroking the chin, propping the chin in the hand, putting a finger on the cheek. If thinking is a sign of intellectualism, we should presumably be demonstrating this trait by indulging in a lot of hand-to-face contact.

The experts distinguish between "emblems," which are gestures with specific meanings in certain cultures, and gestures, which are intended to assist meaning but lack specific content. An example of an emblem is the hand sign that indicates "OK" in the United States. The same emblem has an obscene meaning in some Mediterranean countries.

An example of a gesture is the waving of hands we all indulge in when searching for a word. Steepling falls somewhere in between; it is a gesture without any specific meaning, but it is more deliberate than a mere waving of the hands. The best that can be said about it is that it may signal intellectual pretensions on the part of the communicator!

5. High-status people demonstrate their dominance of others by touching them. Another widely accepted belief is that powerful people in society-often men-show their dominance over others by touching them in a variety of ways. In fact, the research shows that in almost all cases, lower-status people initiate touch. And women initiate touch more often than men do.

In his book The Right Touch: Understanding and Using the Language of Physical Contact, Stanley E. Jones describes a study of a public health organization: "The group studied was a detoxification clinic, a place where alcoholism is treated. This was an ideal setting in which to study status, sex roles, and touching.… [The] findings showed two clear trends. First, women on the average initiated more touches to men than vice versa. Second, touching tended to flow upwards, not downwards, in the hierarchy."

6. People smile when they're happy. People smile for all sorts of reasons, only one of which is to signal happiness. Ekman describes many kinds of smiles, from the "felt" or true smile to the fear smile, the contempt smile, the dampened smile, the miserable smile, and a number of others. Daniel McNeill, author of The Face: A Natural History, says, "Smiling is innate and appears in infants almost from birth....The first smiles appear two to twelve hours after birth and seem void of content. Infants simply issue them, and they help parents bond. We respond; they don't know what they're doing. The second phase of smiling begins sometime between the fifth week and fourth month. It is the "social smile," in which the infant smiles while fixing its gaze on a person's face."

Whatever their origin or motivation, smiles have a powerful effect on us humans. As McNeill points out, "Though courtroom judges are equally likely to find smilers and nonsmilers guilty, they give smilers lighter penalties, a phenomenon called the 'smile-leniency effect.'"

7. Voices rise when speakers are angry. Again, nonverbal communication reliably signals the presence of emotion, but not the specific emotion. A rising voice is associated with a variety of emotions, including anger, but also nervousness, fear, excitement, hysteria, and others. You must always consider the communicator and the context carefully. Experts like Ekman warn that unless you have a good understanding of someone's basic communication patterns, you will have little hope in accurately deciphering the person's less routine signals.

"The best-documented vocal sign of emotion is pitch," says Ekman. And yet he also says, "While most of us believe that the sound of the voice tells us what emotion a person feels, scientists studying the voice are still not certain."

8. You can't trust a fast-talking salesman. The belief that speed and deception go together is a widespread and enduring one. From the rapid patter of Professor Hill in The Music Man to the absurdly fast speech of the FedEx guy in the TV commercial from a few years back, we react strongly-and suspiciously-to fast talk. People talk at an average rate of 125 to 225 words per minute; at the upper end of that range listeners typically find themselves beginning to resist the speaker. However, as Ekman says, the opposite is greater cause for suspicion. Speech that is slow, because it is laced with pauses, is a more reliable indicator of deception than the opposite.

"The most common vocal deception clues are pauses," says Ekman. "The pauses may be too long or too frequent. Hesitating at the start of a speaking turn, particularly if the hesitation occurs when someone is responding to a question, may arouse suspicion. So may shorter pauses during the course of speaking if they occur often enough. Speech errors may also be a deception clue. These include nonwords, such as 'ah,' 'aaa,' and 'uhh'; repetitions, such as 'I, I, I mean I really...'; and partial words, such as ‘I rea-really liked it.'

"These vocal clues to deceit-speech errors and pauses-can occur for two related reasons. The liar may not have worked out her line ahead of time. If she did not expect to lie, or if she was prepared to lie but didn't anticipate a particular question, she may hesitate or make speech errors. But these can also occur when the line is well prepared. High detection apprehension may cause the prepared liar to stumble or forget her line."

Most of the research into nonverbal communications shows that people are not very good at masking their feelings. Emotions do leak out regularly, in many ways. And yet, the research also shows that most of us are not as good at decoding those emotions as we would like to think. Young people are significantly worse at both signaling emotions and reading them. Although we do learn as we grow older, we should remain wary; in the end, body language conveys important but unreliable clues about the intent of the communicator. The more information you can get about the clues you are trying to decode, the more likely you will be to decode them correctly.