How Does Lie Detection Begin?

No matter how much we might want to fully automate the work of a profiler or verifier, it’s not really possible. Of course, there are recurring steps in our work, procedures we follow, and rules we stick to. However, as you probably already know, there’s no such thing as a 100% reliable sign of lying that would let us confidently declare someone is being dishonest. Fortunately or unfortunately, our noses don’t grow like Pinocchio’s when we lie. There’s no absolutely true indicator anywhere in the body. We can’t determine if someone is lying based on a single sign. Lie detection always involves gathering information from multiple channels.

There are plenty of stereotypes about how liars give themselves away, from scratching their nose to avoiding eye contact. If it were really that simple, there wouldn’t be so many deceived people—or so many professionals in the verification field. It would be enough to spot one sign and make a decision. But that’s not the case; you have to consider the context and see the bigger picture.

For example, when we start an interview with a candidate, we don’t immediately interpret their nervousness, self-soothing gestures, or uneven breathing as signs of hiding information. Everyone needs time to adapt to a new situation. Instead, we look for patterns in the appearance of possible signs of lying across different channels: physical state, behavior, and speech.

Understanding the Channels of Lie Detection

You’ve probably heard about microexpressions that reveal true or hidden emotions, emblematic leaks that send mixed messages, and speech patterns that can be specific signs of deception. Spotting or “catching” a microexpression during a check or conversation—and then interpreting it correctly—isn’t easy. People also have their own mannerisms (not the 16th-century European art movement, but habitual facial behaviors). Emblematic leaks don’t happen as often as we’d like, and for some people, they’re just a regular part of their communication. Think of Vladimir Zhirinovsky’s twitching shoulders, a Soviet teacher’s middle finger pointing at the blackboard, or a gesture of admiration expressed by shaking the head as if to say, “That was incredible!” Paul Ekman’s books explain all this clearly and simply. But in practice, when we spot leaks in someone’s face or body, we realize they’re not always a “100% sign of lying.”

And then there’s speech. It takes skill to distinguish between someone’s habit of answering a question with another question, the influence of their “General” metaprogram in their word choices, or a genuine case of forgetfulness versus the speech patterns of a liar.

Baseline Behavior: The Starting Point of Lie Detection

This brings us to a key point: lie detection starts with identifying a person’s baseline behavior.

Baseline behavior (BLB) is how a person acts in a normal setting, during conversations about neutral topics that don’t cause stress or emotional reactions. In simple terms, it’s the “zero mark”—the standard you’ll use to compare their behavior when verifying their statements. Lie detection really begins with comparing two behavioral states. It’s all about spotting changes.

For example, we once had a case where we were asked to find out if a woman was being faithful to her boyfriend. In her normal state, she constantly shook her leg, which might seem like nervous behavior. But that was her BLB. When we asked her about another man, her leg suddenly stopped moving and stayed still until the topic changed. The main takeaway: use simple, unemotional questions about things like nature or the weather to figure out what your conversation partner’s usual behavior looks like.

What Makes Up Baseline Behavior?

Baseline behavior includes external factors such as:

• Skin color
• Eye behavior
• Gesturing habits
• Usual postures
• Breathing patterns
• Temperature characteristics
• Facial habits and mannerisms
• Speech habits
• Voice characteristics
• Response latency
• Speed of answering questions
• Other behavioral features

Only after establishing the BLB do we move on to presenting a test stimulus to the person. And only after collecting enough data—after reaching a “critical mass” of signs—can we draw conclusions about the presence of deliberately concealed information.

Common Pitfalls in Lie Detection

In practice, we’ve encountered “deceptive” elements in baseline behavior, such as:

• Left-sided illustrators
• Consistently one-sided shoulder shrugs
• Congenital facial asymmetry, like a contemptuous smile
• Fear as a basic facial pattern
• Frequent blinking as a baseline
• Self-soothing gestures in any context
• Speech patterns typical of liars as habitual speech
• Health issues causing signs of stress in the autonomic nervous system
• And many more

We could easily make the wrong judgment if we only looked at these behaviors in isolation. Fortunately, we remember that in lie detection, what matters are the changes—deviations from the BLB. So don’t go looking for a mythical “smoking gun.” Instead, observe your counterpart and objectively evaluate their reactions as a whole.