Signs of Lying: How to Spot Potential Deception

This article is an excerpt from the Shortform book guide to "What Every Body Is Saying" by Joe Navarro and Marvin Karlins. Shortform has the world's best summaries and analyses of books you should be reading.

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What are the telltale signs of lying? What signs should look out for to confirm your suspicions that a person isn’t being truthful?

Deception is a complex psychological process, and no behavioral cue can tell you with certainty that someone is lying. However, as a general rule of thumb, when someone is trying to deceive you, they’ll exhibit insecure body language.

Keep reading to learn how to spot potential deception, according to former FBI agent Joe Navarro.

How to Detect Deception

According to Joe Navarro, the author of What Every Body Is Saying, body language can reveal signs of lying. He explains that people who are lying tend to exhibit more insecure behaviors because deception takes mental effort and often causes stress, which can trigger some limbic responses that we can identify.

(Shortform note: Neuroscientists explain why lying is more stressful and mentally taxing: it requires you to use your brain’s executive function and, more specifically, your working memory. This is because you need to predict the direction the conversation might go and determine what you need to say to maintain your lie. One study showed that lying increased both mental workload and reaction time.)

However, no behavioral cue can directly indicate whether or not a person is lying. Research has shown that even the most experienced behavioral analysis experts have, at best, a 60% chance of correctly guessing whether someone’s lying. For this reason, he cautions you to be careful when using body language alone to accuse someone of deception.

(Shortform note: Other researchers echo Navarro’s warning, adding that it’s a common misconception that you can tell if someone is lying based on the way they’re acting. A 2003 study by psychologist Bella DePaulo found that out of 102 nonverbal cues gathered from 116 experiments, none could reliably indicate deception. Because lie detection mistakes can have costly consequences in the criminal justice system, psychologists are looking into alternative strategies to detect lies, such as allowing interviewees to talk more freely so that they might contradict themselves.)

Behaviors That May Indicate Deception

While the signs of insecurity we’ve discussed earlier indicate discomfort and can reflect possible deception, Navarro offers two more specific deception-related signs:

1) Delayed or Inconsistent Behavior: Navarro explains that people who are lying often have delayed responses, since they’re consciously trying to behave in a way that matches their words. For instance, if someone says that they agree with you, observe whether their nod occurs at the same time as their words. If they start nodding after they speak or even start shaking their head side-to-side, this delay or inconsistency in behavior may indicate inauthenticity.

(Shortform note: These delayed or inconsistent body signals are what psychologists refer as nonverbal leakage. This term was popularized by psychologist Paul Ekman in the 1970s, who argued that the face has the highest sending capacity of signals—it’s the most easily visible body part with nuanced expressions. The feet, hands, and legs, then, have lower sending capacity in that they’re more easily concealed and less expressive. However, like Navarro, Ekman acknowledges that the face can also produce confusing signals and suggests looking for contradictory expressions.)

Similarly, people who are lying might not be displaying the appropriate emotions for the situation. For example, if someone asks to borrow money for an emergency, they should be acting anxious and urgent rather than relaxed and collected.

(Shortform note: While, as Navarro suggests, inappropriate emotions can indicate deception, research shows that people also display unexpected emotions during intensely emotional situations. You might be familiar with some common examples: crying when happy or laughing when sad. Psychologists theorize that this behavior isn’t deceptive, but used as a form of emotional regulation. Essentially, when you’re overwhelmed with positive or negative emotions, you express an opposite reaction to lower the intensity of your feelings.)

2) Uncommitting Behavior: Navarro explains that people who are lying tend to be less committed to their statements and use fewer grand gestures to convince you of what they’re saying. A person might give a half-hearted shrug instead of a full one, or they might cover their mouth while speaking.

(Shortform note: Although Navarro writes that people who are lying use less emphasis to support their words, Robert Greene argues the opposite: that deceptive people may intentionally use exaggerated gestures to distract you from their true thoughts. Greene explains that the mouth and face are likely to be the most animated body parts and advises you look for other parts of the body that might be tense.)

One specific behavior that reflects commitment is whether someone gestures with their palms up versus palms down. Navarro explains that raising your palms up when you speak suggests you’re asking to be believed, whereas facing your palms down while speaking demonstrates emphasis.

(Shortform note: Researchers explain why palm gestures have these meanings: Evolutionarily, our distant ancestors used palm-up gestures in a submissive crouch position and palm-down gestures as part of a push up into a higher, more aggressive stance. More specifically, palms-down signals denial or interruption while palms-up signals an offering or request. In fact, palm-up gestures are so deeply rooted in our evolutionary history that they’re still common in apes. For apes, researchers believed these gestures occurred originally as a means to catch fallen food while another ape was eating, which later evolved into a communication signal.)

Signs of Lying: How to Spot Potential Deception