How To Tell if Someone Is Lying to You, According to a Communication Pathologist and Cognitive Neuroscientist

Communicative pathologist and cognitive neuroscientist Caroline Leaf, PhD, says there are slew of speech patterns, visual cues, and physical signs exibited when someone isn’t telling the truth. While these affectations might be able to discern if someone is lying to you, there’s a bit more to it, she says.

What are physical signs someone is lying?

According to Dr. Leaf, creator of Neurocycle, common physical signs that someone is lying might include sweating, shakiness, darting eyes, stuttering, the use of non-congruent gestures, and excessive fidgeting. It’s important to remember two key things here, though.

First, these signs might be tells that someone is lying—they’re not guarantees. After all, some people are just more anxious and/or fidgety than others. “Oftentimes these physical symptoms can also equate to having social anxiety and so if someone always uses these symptoms in their speech, it isn’t safe to assume they are lying,” Dr. Leaf says. “However, if there is a change in how they normally speak—if these physical signs are an irregular pattern in their conversation—it could indicate there is a possibility that they are lying.”

Second, Dr. Leaf is quick to point out that these are just some of the many physical signs that could present while someone is actively lying. All in all, physical signs that someone is lying tend to be indicative of avoidance. For example, darting eyes is an avoidance of direct eye contact, stuttering could be a nervous side effect of trying not to let the truth spill, and so on.

What are speech patterns that indicate someone is lying?

While stuttering can be considered a speech pattern that pops out under duress (like, say, while actively lying), Dr. Leaf says that another vocal cue is under or oversharing. “Sometimes people who are lying may give elaborate details or they may also give too little details,” she says.

In addition to what they are (or aren’t) saying, Dr. Leaf says that inflection plays a role, too. “There may be a change in their tone of voice, they may mutter or trip over words,” she says.

Lastly, Dr. Leaf points out that when someone is actively lying, it’s entirely possible that they won’t be able to maintain their falsehoods. “You may hear different stories and details of stories,” she explains.

What are visual cues that indicate someone is lying?

Visually, Dr. Leaf says that body language could be an indicator of lying. “There may be a sudden shift in their body language when they start to lie—they may display some nervous cues—they may avoid eye contact or cover their mouth—especially if it is not how they normally communicate,” she says.

That said, while body language can indicate that someone is lying, it’s not innately a telltale sign.

“It is important to understand that a person’s body language may change when they are lying and it may not,” says Dr. Leaf. “Oftentimes if we form perceptions based on body language alone, it can lead to a lot of miscommunication in relationships.”

What To Do if You Think Someone Is Lying to You

If you think that someone is lying to you based on physical, verbal, and visual cues you’ve been noticing, it’s important to consider what they might be lying about.

Lying with malicious intent (for any reason other than a happy surprise, like a birthday, engagement, or baby announcement) can be very damaging to mental health as well as relationships of all kinds. “Smaller lies may be less damaging on a large scale but are still hurtful and can lead to mistrust in relationships,” Dr. Leaf says. “Then there are big lies or betrayals of trust that can ruin relationships, which then lead to a lot of work to repair, but it is so important to sort out the impact of lying out.”

If you think that someone is fibbing about a joyous upcoming moment, let it slide (unless you hate surprises). If however, you think they’re lying about something serious, you may want to confront them about it and determine if you want to walk away or hear them out and work through it.

“It’s safe to assume that most people in the world have lied at least once in their lifetime and there are many different reasons why,” Dr. Leaf says. “Some people may be really hurting and they lie about their feelings, or they may be going through serious mental struggles like addiction or eating disorders or trauma and they lie to cover it up. There are, however, people who lie to hurt others or lie with bad intentions. Unfortunately, being honest can be hard but ultimately being honest with others can help you be honest with yourself and respect yourself and others more.”