The Bizarre Way A Person's Arm Can Be Used As A Lie Detector — & How To Use It To Your Advantage
It turns out lying actually affects our bodies, not just our minds.
fizkes | Shutterstock We all know that most people have certain "tells" when they're lying — that look in their eye or that subtle change in their voice that gives them away.
But it turns out there's also an involuntary physiological response we all have when telling a mistruth that gives us away instantly, and it's as simple as raising an arm.
A person's arm can be used as a lie detector because of the way lying affects our brains.
Sounds like a bunch of nonsense, of course, but it really is true. Harvard-trained sociologist and author Dr. Martha Beck recently demonstrated this weird phenomenon during an appearance on Steven Bartletts' "Diary of a CEO" podcast.
In it, she told Bartlett to hold out his arm. As she applied pressure to it, she asked him to repeat certain phrases — some that were true, and one that was an outright lie.
When Bartlett said things like "I love fresh air," he was able to withstand Beck pushing on his arm. But when he said "I love to vomit," — the lie, if that wasn't obvious — his arm immediately collapsed.
"When I said I love to vomit, it was like I wasn't actually connected to my strength and my hand," a bewildered Bartlett said. "It was like I was inside my head, so I couldn't also at the same time, think about you… It was like there was two different systems."
Science has found that lying essentially overloads our brains, making our bodies compensate.
"When we lie, our bodies get very weak," Beck explained to Bartlett. "Because the body lives in reality. The body is honest. Only the mind, and only the verbal mind can lie to us and tell us things that we can believe even though they're not true."
Neuroscience has discovered that truth and lying ignite our brains in completely different ways that make our brains work far harder to keep up a ruse. Using techniques like fMRI imaging, scientists found that being truthful initiates four parts of the brain, whereas lying kicks in seven, nearly twice as many. This means that the brain has less bandwidth for physical tasks — or "our bodies get very weak" in Beck's words.
Of course, when you're just doing a fun test like this, there are no consequences like there are with actual, real-life lying — no feelings to get hurt, no trouble to get in. So imagine, then, the impact ACTUAL lying might have, especially if the person you're lying to is yourself.
Beck and others say this science underlines the power of being truthful to ourselves.
There are all kinds of theoretical uses for this arm test of course — tons of women in the comments of Bartlett's video joked that they were going to immediately push on their partner's arms and ask if "she's just a friend."
But it has other uses and implications as well. The field of applied kinesiology, for example, has related this research to sports and fitness. For example, if lies weaken the body and you hate the workout you're telling yourself you love in order to get through it, you're probably weakening your body's performance and response to that workout.
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But Beck put this phenomenon into even sharper focus. She told Bartlett of an exercise she uses during speaking engagements, in which she asks attendees if they're truly comfortable in their seats. They always insist they are, despite sitting on hard, unpleasant folding chairs or auditorium seats.
That discomfort is just part of attending something like a conference, of course, but it is nonetheless technically a lie. While it makes sense to basically gaslight yourself in this manner to get the benefit of a conference lecture, Beck cautions that we often do this exact same kind of lying to ourselves about far more important parts of our lives, too.
She explained that people who are in jobs, relationships, and religions where they're not comfortable basically do what we do with an uncomfortable chair at a conference — convince themselves that it's just the trade-off for having a good job, not being alone, or whatever the case may be.
"They think they're comfortable, but they're getting sick," Beck said. "Or they're getting addicted to a substance because they're trying to numb the discomfort they won't acknowledge." It all, to some extent at least, comes back to the way dishonesty weakens the body.
Honesty is of course often uncomfortable in and of itself. But it doesn't weaken us like lying has been proven to do. So you could say that when we're not honest we're actually working against ourselves — and being truly honest just might be the key to manifesting a better version of our lives and ourselves.
John Sundholm is a writer, editor, and video personality with 20 years of experience in media and entertainment. He covers culture, mental health, and human interest topics.