How to Tell if Someone Is Lying to You: 3 Verified Ways

This article is an excerpt from the Shortform book guide to "Becoming Bulletproof" by Evy Poumpouras. Shortform has the world's best summaries and analyses of books you should be reading.

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Want to know how to tell if someone is lying to you? How do professionals detect lying? What should you look for?

As a former interrogator, Evy Poumpouras knows how to understand others’ true feelings and intentions through careful observation. In Becoming Bulletproof, she argues that learning how to tell if someone is lying to you can help you to get more out of your relationships.

Read on to learn how to tell if someone is lying to you, according to Poumpouras’s three methods.

How to Tell if Someone Is Lying

In Becoming Bulletproof, Evy Poumpouras argues that learning how to understand people through their words and actions can help you become stronger and more resilient in your personal and professional life. If you know what to look for, you can come to a deeper understanding of people’s emotions and feelings, which in turn will help you get more out of your relationships. Ultimately, when we seek to understand others, we seek to know if we can trust them, which is why Poumpouras mainly focuses on how to tell if someone is lying to you.

#1: Avoid Categorizing Others

Poumpouras claims that before you can learn how to read people and tell if they’re lying to you, you must let go of any biases and tendencies to categorize or stereotype others. We like to put people into simplified groups based on limited information and our own biases: People are either good or bad, smart or stupid. Reality, though, isn’t so black and white. People are complicated, and when we place them into simplified categories we ignore the many complexities of their personality and behavior, which makes it nearly impossible to fully understand them.

(Shortform note: In Biased, Dr. Jennifer Eberhardt explains why we categorize people and how this leads to bias: We categorize people unconsciously as a way of simplifying the complex world around us. When we place people in certain categories, it makes it easier to make judgments about one person based on how you view other people in the same category. Sometimes this can be innocuous, like when we see someone fit and assume they go to the gym a lot. But this categorization also leads to harmful stereotypes, like assuming a person is dangerous due to their skin color, or stupid because of the way they talk.)

#2: Establish a Baseline

To tell if someone is lying to you, Poumpouras claims that you need to first establish a baseline for a person’s behavior and then look for “red flags”—unusual changes—in their speech or mannerisms that indicate they’re lying.

To establish a baseline for someone’s behavior, observe them in a casual situation first and get a sense of how they normally act. Focus on their posture, facial expressions, the words they use, and the way they speak.

Then, look for multiple red flags when trying to identify lies. If you notice multiple changes in behavior or mannerisms, you can be reasonably certain that you’re being lied to.

For example, let’s say you think a coworker you don’t know well is taking your food from the shared refrigerator. Instead of directly asking them if they’re eating your food, strike up a casual conversation first. Then, when you ask them what you want to know, look for changes in their behavior.

Why Familiarity Doesn’t Always Help You Detect Lies

Poumpouras argues that knowing how someone normally behaves helps you know if they’re lying to you. Because of this, you may assume you’ll be able to tell when a close friend or loved one is lying. But this isn’t necessarily true, and there are several reasons you may be bad at detecting a loved one’s lies:

– We trust our loved ones and often give them the benefit of the doubt.

– We fear that accusing someone of lying is rude and that it might make them uncomfortable or even angry.

– We lack the motivation to dig deeper into a loved one’s story to see if it’s a lie.

#3: Look for Common Red Flags

Now let’s look at the most common red flag behaviors to look for when someone is lying to you. Although everyone behaves differently, Poumpouras claims that there are certain behaviors that people commonly exhibit when they lie. These behaviors fall into two categories: body language and verbal cues.

Body Language

Poumpouras argues that our body language reveals a lot about what we’re thinking, and if you know what to look for, it can give a glimpse into someone’s true feelings or intentions. Here are some of the most telling ways body language can give people away:

Micro-expressions: When someone is trying to hide something, they may give away their true feelings or thoughts in a series of micro-expressions—subtle facial cues that last less than half a second.

Eye Movement: People tend to use particular eye movements when in a conversation. Some people make consistent eye contact. Some look to the side when recalling information. If you know how they normally use their eyes in particular situations, a change in these behaviors can be a telltale sign of a lie.

Mouth Movement: People tend to hold a lot of tension in their mouth and jaw. They may clench their jaw or grind their teeth when they’re angry. When nervous, some people bite their lips or tighten their mouth. Both these movements might indicate a lie.

Hand Movement: We use our hands a lot when we talk, so changes in hand movement can be telling: For instance, if a person who normally gestures often puts their hands in their lap, they might be lying to you.

Posture: When people feel uncomfortable or defensive because they’re lying, they may cross their arms. If they feel vulnerable, they may put their weight on their elbows or rest their head in their hands to try to support or comfort themselves.

Observing Body Language in Different Personality Types

Knowing how different personality types typically use body language can enhance your lie detection abilities. In Surrounded by Idiots, communication expert Thomas Erikson separates people into four personality types (red, yellow, green, blue) and explains how they use their body language to communicate. If someone is using body language that differs from their typical behavior, this could be a sign that they’re lying to you. Here’s a brief overview of the four personality types and the body language they use:

Red: Red types are extroverted, ambitious, and confident. They seek to dominate others socially. Their body language will be direct and aggressive. They’ll use sharp hand gestures, make direct eye contact, and usually carry a serious facial expression.

Yellow: Yellow types are extroverted, ambitious and confident. They seek to influence or inspire others. They’ll usually be less aware of personal space while smiling frequently and seeming relaxed and comfortable.

Green: Green types are introverted, cooperative, and patient. They appreciate routine and stability. They’re usually attentive listeners and smile in a friendly way, but are more touch averse when it comes to strangers.

Blue: Blue types are introverted, obedient, and private. They seek to conform and do things as they’re meant to be done. They use little motion in their body language and facial expressions. They value personal space, and will likely show discomfort if you get too close to them.

Verbal Cues

Poumpouras provides examples of the most common verbal cues that may indicate if someone is lying to you:

Answering with a question: People often use this as a stalling tactic. They may ask if you’re talking to them or repeat the question back to you.

Saying you’re wasting their time: People may say things like, “I don’t have time for this” or ask, “Are we done yet?” This may indicate they’re uncomfortable with the questions asked or topics discussed.

Minimizing the issue: People may try to move on from the subject by minimizing its importance. They may ask what the big deal is or say that an issue or question you bring up isn’t that important.

Lying by omission: This is a tactic people use to get others to leave them alone. They’ll say they don’t know the answer or forgot to avoid further questioning.

Over-dramatic answers: People may try to overcompensate for their lie by swearing on their children or vehemently denying an accusation.

Using present tense: When people tell a true story, it’s usually in the past tense. If they tell a story in the present tense, it may indicate they’re making up the story on the spot.

How to Ask Questions That Trigger Red Flags

Research suggests that using verbal cues to detect lies is more effective than using body language. Because of this, knowing how to ask the right questions to uncover lies can be a valuable skill. Here’s some advice on asking good questions:

Don’t ask meaningless questions: Every question should be a calculated attempt to discover the truth.

Listen as much as possible: Pay close attention to how others answer your questions and don’t interrupt them.

Remain casual and curious: If you’re too formal or aggressive, the person you’re questioning will get defensive and you won’t get as much out of them.

Include the aspect of time in your questions: If someone is lying to you, they’ll often get verb tenses wrong or contradict themselves when it comes to time.

How to Tell if Someone Is Lying to You: 3 Verified Ways