Imagine two people saying exactly the same thing: “I’m glad to see you.” One says it with a smile, looks you straight in the eye, and sounds genuinely pleased. The other says the same words in a flat voice, barely looking up from their phone. Formally, both have said the same thing, yet one is easy to believe while the other leaves us wondering how sincere they really are.

Why does this happen? Because during a conversation we take in far more than the literal meaning of words. We notice tone of voice and facial expression, follow someone’s gaze, gestures, posture and movements, and even register the distance they try to keep from us. Most of this analysis happens without conscious effort, as though an internal detector were automatically responding to signs of sincerity, anxiety, irritation and much more.

All of these signals are usually referred to as nonverbal communication. They accompany almost every interaction and can support and enrich what is being said—or contradict it completely. But does that mean gestures and tone should always be trusted more than words? Can we really tell from someone’s behavior what they think and feel?

Sometimes it seems that nothing matters more in a conversation than words. After all, words are how we share information, ask questions, and explain our thoughts and feelings. In reality, however, communication is much more complex. During a conversation, the brain is constantly gathering many signals at once, trying to understand not only what someone is saying, but also how they feel while saying it, how sincere they are, and whether they can be trusted.

Much of this has to do with the fact that human communication existed long before any form of writing. Even sophisticated spoken language developed much later than our ability to interpret other people’s behavior from a wide range of cues. For thousands of years, people had to judge the intentions of others by facial expressions, movements, voices and behavior. This way of perceiving others was so important for survival that over time it became largely automatic. We rarely think about it, yet we still analyze the person we are speaking with at an unconscious level.

We often sense another person’s attitude before we begin to think carefully about the meaning of their words. Sometimes only a few seconds are enough to feel openness and friendliness. At other times, a strange tension seems to hang in the air even though nothing unpleasant has been said. Of course, first impressions can be badly mistaken, but the mechanism itself is natural and deeply rooted in us.

In psychology, signals that accompany speech but are not words are known as nonverbal communication. They include facial expressions, gaze, gestures, posture, movement, intonation, pace of speech and much more. Nonverbal communication usually works closely alongside spoken language. The two channels operate together, complementing each other and helping us convey meaning more precisely.

Nonverbal communication is everywhere. Imagine a group of friends. One of them says to another with an entirely serious expression: “Well, that’s it—you’re doomed now.” If we considered only the words, we might assume something unpleasant had happened. But the others start smiling, and everyone immediately understands that it was just a joke. We know this not from the words themselves, but from nonverbal cues such as a playful tone of voice.

Now imagine another situation. You hold a door open for a stranger or help them pick up something they have dropped. They respond with a simple “Thank you.” It may sound warm and appreciative, or it may be delivered so dryly and irritably that it feels more like annoyance. The words are the same, but the impression can be completely different.

Or consider a situation familiar to many parents. A child comes home from school and says: “Everything’s fine at school.” But the backpack is thrown into a corner, the jacket comes off in sharp, abrupt movements, and the child gives one-word answers before quickly disappearing into their room. Most parents immediately sense that something unpleasant has happened. They may not know what it was, but they already feel that things are not quite as simple as the words suggest.

Sometimes nonverbal communication helps us hear what has been left unsaid. Imagine meeting an old acquaintance. They smile and politely ask how you are, yet keep glancing at their watch, answer in short phrases, and take a step back, increasing the distance between you. You will probably realize quite quickly that they are in a hurry or, for some reason, do not want to continue the conversation. Out of politeness, they may never say so directly.

Another familiar example comes from text messaging. An ordinary exchange can sometimes turn into an argument. One person writes a short “Thanks,” while the other interprets it as irritation. Yet the sender intended no negative meaning at all. Text simply lacks the tone of voice, facial expressions and gestures that would help us understand mood in a face-to-face conversation. It is no coincidence that people use emoticons and emojis so often: they can partly replace the nonverbal signals that are missing when we communicate through a screen.

Sometimes words and nonverbal signals contradict each other. Imagine someone telling you, “Everything is fine,” while avoiding eye contact, answering only after a long pause, looking visibly tense and speaking with a trembling voice. Most of us would sense that something is wrong and would hesitate to take the words at face value. This does not necessarily mean the person is lying. They may simply be tired, anxious, or unwilling to discuss what is happening. But moments like these show why, if we want to understand a situation accurately, it is important to listen both to the words and to everything that accompanies them.

Once we learn about nonverbal communication, it is natural to want to learn how to “read” people. It can sound simple: memorize a few gestures, notice where someone is looking or how they hold their arms, and you will supposedly be able to tell exactly what they feel. A huge number of popular books, videos and articles are built around this idea.

In practice, things are much more complicated. The most common mistake is drawing a conclusion from one cue or a small number of cues. Suppose someone crosses their arms. Does that mean they disagree with you, have become defensive, or do not trust you? Not necessarily. Perhaps they are simply cold. Perhaps their arms are tired and the position feels more comfortable. Or maybe they simply like standing that way. The same gesture can have many different causes.

Nor should we assume that someone is lying simply because they look away, blink more often, or become visibly nervous. Nervousness is far from being a reliable sign of deception. One person may be anxious during a job interview, another before speaking to their manager, while someone else may simply feel uncomfortable around strangers. From the outside these situations can look very similar even though the reasons behind them are completely different.

Context is just as important. Imagine someone repeatedly looking at their watch during a conversation. It would be easy to conclude that they are bored or being disrespectful. But perhaps an important meeting starts in a few minutes, they are waiting for an urgent call, or they are worried about being late to pick up their child from school. The very same behavior can mean entirely different things depending on the circumstances.

Individual differences also matter a great deal. Some people gesture actively even in an ordinary conversation, while others hardly gesture at all. Some find eye contact easy, while others feel very uncomfortable looking directly into someone’s eyes. That is why professional psychologists tend to pay less attention to isolated movements and more to changes in a particular person’s usual behavior.

Nonverbal communication also depends heavily on culture. A gesture considered friendly and ordinary in one country may carry a very different meaning in another. Even expectations about interpersonal distance, acceptable eye contact and emotional expression vary significantly between communities. There is therefore no universal dictionary of body language that works in the same way for everyone.

This is why bold claims such as “five gestures that reveal a lie” or “how to tell in one minute that someone is deceiving you” should be treated with caution. Such advice is attractive because it promises quick answers to difficult questions. Yet research into human behavior shows that there are no reliable, universal signs of lying. Behavior depends on many factors and needs to be understood as a whole rather than reduced to isolated details.

Nonverbal communication really can help us understand other people better. But it is not a magical key to someone else’s thoughts and not a tool for instantly diagnosing character or intentions. It simply provides additional information that needs to be considered alongside words, context and the individual characteristics of the person involved.

Understanding nonverbal communication can make our conversations more attentive and more conscious—but only if we use that knowledge not to hunt for hidden meanings or expose other people, but to improve mutual understanding.

If someone’s words seem not to match their emotions, there is no reason to conclude immediately that they are hiding something or lying. They may simply be struggling to find the right words because they are nervous. In fact, this can sometimes reflect a strong desire to be sincere and a fear of saying the wrong thing. Often it is enough to ask: “Are you sure you’re okay?” or “It seems like something is bothering you. Do you want to talk about it?” This approach is often far more effective than trying to decipher another person’s thoughts on our own.

It is equally important to remember that nonverbal communication works both ways. While we observe others, they are trying to understand us in exactly the same way. We may genuinely want to support someone, yet speak in a slightly flat voice or keep getting distracted by our phone. As a result, our words may come across very differently from what we intended. It is therefore useful to pay attention to how our own words and behavior might look from the outside.

We should not turn nonverbal communication into a single universal tool for judging other people. The more convinced we become that we can read someone’s emotions and intentions without error, the greater the risk that we will get them wrong. We may mistake ordinary tiredness for dislike, thoughtfulness for arrogance, or anxiety for an attempt to hide something. Nonverbal cues are better treated as additional information than forced into simplistic templates taken from the Internet.

If someone’s behavior is difficult to understand, an ordinary conversation remains the most reliable way to clarify the situation. A sincere question and a willingness to listen are almost always more effective than trying to construct an explanation from nonverbal cues alone.

Nonverbal communication is not a collection of secret signs and not a way to read other people’s minds. It is a natural part of human interaction. It can help us understand one another better, but only when we consider it together with words, context and the individual person.