If You Notice Your Partner Doing This, They're Lying to You, Studies Say

Wondering if your partner is lying to you? According to a recent article in Psychology Today by Jack Schafer, PhD, a professor at Western Illinois University's Law Enforcement and Justice Administration (LEJA) Department as well as a retired behavior analyst for the FBI, there’s a simple way to catch someone lying to you: it’s all in the eyes. Read on for more on Schafer’s insight, and for more relationship tips, check out The Worst Thing You're Saying to Your Partner Without Realizing It.

All people’s bodies are different, which is exactly why Schafer says you need to establish a baseline for this particular test to work, just as you would during a polygraph lie detector test. Start by observing their characteristics under normal circumstances to help establish what the truth looks like, versus a deception.

Drawing on a series of studies, Schafer explains that when people are lying, their pupils will frequently dilate because “lying causes an increase in cognitive demand” and “pupil dilation normally indicates an increase in cognitive demand.” As your partner strains to formulate a story or logical explanation that lacks truth, their brain processes it differently. After all, it's a mental workout to hold two opposing ideas in mind at once, then to express one while suppressing the other.

Of course, some people are better at lying than others—and research shows that people can get better at it with effort. One study published in the journal Frontiers in Psychology enlisted 48 college students in China to see if lying could become more automatic with practice. The subjects were instructed to answer a set of questions either truthfully or deceptively, as quickly as they could. Then, they were asked to speed up their responses, and make fewer mistakes with their lies. The researchers found that the students did indeed become more efficient liars with practice, and that it appeared to require less cognitive effort. In other words, if your partner is practiced at lying, it would be harder to know from a physical tell.

That said, if the relationship is built on mutual respect and trust, clues won't be necessary. Instead, have a frank conversation about your concerns and give them the benefit of the doubt.

Wondering what other physical signs can clue you in to a partner's dishonesty? Read on for four more research-backed ways to spot a deceit, and for more relationship red flags, Your Relationship Is Doomed If Your Partner Does This, Experts Say.

1 | They show signs of stress.

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For most people—especially those who value honesty in general—bigger lies are more physically straining to tell. If you notice signs of stress in your partner and the facts aren’t adding up, you may have detected their deceit.

Roger Strecker, Sr., a behavioral analysis interrogator with over 30 years of law enforcement experience, recently told NBC News, “The limbic and basal ganglia systems are two critical components of the human brain controlling processing of stress and visible nonverbal deception attributes humans exhibit.” This might include changes in breathing, perspiration, touching of the face, fidgeting, or anything else that diverges from baseline behavior. And for the latest relationship news delivered straight to your inbox, sign up for our daily newsletter.

2 | They provide too much or too little information.

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It’s common for people to skimp on the details while telling a lie—after all, the more you say, the more you can be questioned about later.

But experts say that it is also common for liars to overshare in an attempt to distract with seeming confidence. "When someone goes on and on and gives you too much information—information that is not requested and especially an excess of details—there is a very high probability that he or she is not telling you the truth," Lillian Glass, a behavioral analyst and body language expert told Business Insider. "Liars often talk a lot because they are hoping that, with all their talking and seeming openness, others will believe them." And for some situations in which it's okay not to be totally transparent, check out these 23 Things It's OK to Tell Healthy Little White Lies About, According to Experts.

3 | They suddenly become still.

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Telling an uncomfortable lie sets off all sorts of alarms within the body. Some people reportedly react by becoming eerily still while they fabricate their story.

"This may be a sign of the primitive neurological 'fight,' rather than the 'flight,' response, as the body positions and readies itself for possible confrontation," said Glass. "If you observe a rigid, catatonic stance devoid of movement, it is often a huge warning sign that something is off."

4 |

Shutterstock They gesture with their hands only after talking.

Just as the pupils dilate because the brain is processing more complex information, some people also inadvertently cease their hand movements while fibbing.

Traci Brown, a body language expert who has participated in a deception training program with members of the FBI, told Time, “The mind is doing too many things including making up the story, figuring out if they’re being believed, and adding to the story accordingly. So normal gesturing that might normally happen just before a statement happens after the statement." And for more conversational minefields to avoid, This Word You Use Everyday Makes People Think You're Selfish, Experts Say.