How To Tell if Someone Is Lying to You, According to Body Language Experts

If you suspect your partner is cheating or your boss is being less than 100 percent honest, but you just don't know for sure, it can cause tremendous stress and unhappiness.

Studies have shown that humans are bad at spotting lies, despite valuing authenticity in everything from the brands we buy to the celebrities we follow on social media.

Interest in body language and whether it can catch someone in a lie has skyrocketed since the Amber Heard vs Johnny Depp defamation trial but, despite what cop shows and dating experts suggest, untruthfulness isn't so easy to spot.

However, body language experts say there is a reason that certain behaviors set off an internal alarm bell—and can help you determine if someone is being untruthful.

Are There Physical Signs That Someone Is Lying?

A quick Google search on this topic will suggest gestures from scratching your nose to shuffling your feet are signs of dishonesty but according to Mark Bowden, a body language expert and the founder of Truthplane, that's over-simplifying a complex issue.

"There are no absolute signals that anybody could be lying to you," he told Newsweek. "It's a fairytale that you would be able to tell from one signal alone that someone is being deceptive."

Chase Hughes, CEO of Applied Behavior Research and an expert on interrogation and behavior profiling, told Newsweek that most academic research on the physical signs of deception is undertaken in lab conditions—so it doesn't necessarily reflect how people behave in the real world.

"It's like doing a study on PTSD, by telling someone to pretend they have PTSD and studying them. It's very hard to replicate human [behavior] in a lab," he said.

Body language cues can still suggest that someone is being deceitful, however. Look out for physical symptoms of stress or delight around a story, or a sudden change in that person's "normal" behavior.

Hughes said "closed" behavior—such as crossed arms, fingers coming together or other physical signs of fear—can indicate that someone is lying.

"What we're looking for is a spike in stress and fear," he added. "Increased breathing rate, increased blink rate, facial touching—stress does a lot to the body."

There are evolutionary reasons why some behaviors are more closely linked to deception than others, according to Hughes. Freezing or searching for avenues of escape relate to the fight or flight response, while fidgeting can symbolize uneasiness.

"Moving our bodies around is a way to adapt to our environment and ground ourselves in the room," said Hughes. "The need to gain control goes up as deception goes up."

Baseline Behavior

Hughes and Bowden both use baseline behavior as an indicator of deception. After gauging a baseline of how someone normally acts, they can spot deviations in behavior that could be suspicious.

"It just depends on the context," said Bowden. "What were they doing before they started telling the story? What is out of place here from the norm?"

In a perfect world, he added, you'd have the opportunity to get to know someone's baseline behavior beforehand. Although that's not good news for investigators or behavioral scientists, it is helpful if you suspect someone close to you is lying, as you should already know what's normal for them.

While no behaviors are inherently "deceptive," a cluster of unusual mannerisms can be a warning sign. "It's an opportunity to ask more questions," Bowden said.

Establishing a baseline is also why interrogators begin by asking non-threatening questions, to understand how someone acts when they're not under pressure.

"If that person is doing [a certain] behavior all the time, then we ignore it," he said.

Instincts

Ever had an inkling that someone is lying to you, but you're not really sure why? According to Bowden, that's your subconscious trying to keep you safe.

"Science suggests that [human] instinct has about a 50/50 chance of getting it right, but the bias is towards the lie, because it's safer," he said.

Sometimes, however, it's safer to believe whatever you're being told, whether that's to protect yourself emotionally or to adhere to social norms.

"Society would just break down if we didn't accept the stories people tell," said Bowden. "Sometimes, our 'social brain' will trump the bias towards the negative to get on with people."

Successful con artists are great at appealing to this part of our brain—making us ignore our instincts for the sake of those norms. "You'll suspend your usual negative judgments about the situation," Bowden said. "The same is true of predators."

What About Lie Detector Tests?

Experts are divided on whether polygraph machines—better known as lie detector tests—can really determine whether someone is lying.

In theory, the machines detect lies by assessing the blood pressure, respiration and skin conductivity (sweat) of the person being questioned and identifying changes or spikes. Some scientists argue that these responses are an inaccurate way to measure if someone is lying, since there are no proven physiological signs of deception.

According to the American Psychological Association, polygraph testing also has a placebo problem. It states: "One reason that polygraph tests may appear to be accurate is that subjects who believe that the test works and that they can be detected may confess or will be very anxious when questioned. If this view is correct, the lie detector might be better called a fear detector."

Hughes believes that a polygraph machine can play a role in an interrogation, but "is better for getting information from a person than it is at detecting deception."

"The polygraph reviewer is getting a baseline of normal behavior and is looking for deviations from that—respiration, sweat, blood pressure, stress response.

"A good interrogator isn't going to say, 'That's 100 percent a lie.' Instead, they're going to say, 'That's a huge red flag and we need to ask more questions.'"