Your gut is not a lie detector

Why trusting your read of someone feels safe

Most of us believe we can tell when something is off. A seller who answers too fast, a match who avoids a question, a caller who sounds rehearsed. We trust the feeling because it usually seems to work.

It seems to work for a simple reason. The communication researcher Timothy Levine calls it the truth-default: people presume that what others say is honest, and since most people are honest most of the time, that presumption is right most of the time. Levine argues it is useful, not foolish. Life would grind to a halt if we doubted every sentence.

The trouble starts when we turn that comfortable default into a test. Believing most people is sensible. Believing you can pick out the one who is lying is a different claim, and the evidence for it is thin.

What a gut feeling checks, and what it does not

Levine's work makes a useful distinction. Demeanor, how someone comes across, tells you very little. Correspondence, whether what they say matches facts you can find out, tells you a lot. A gut feeling runs almost entirely on demeanor.

What the research found

In 2006 Charles Bond and Bella DePaulo pooled 206 documents covering 24,483 people asked to judge lies and truths in real time. Average accuracy was 54%. People caught 47% of lies and correctly believed 61% of truths, which means a liar was more likely to be believed than caught.

Feeling sure did not help. An earlier review of 18 samples found almost no link between how confident people were and how accurate they were. Confidence did rise with a tendency to believe, so feeling certain mostly meant feeling trusting.

And it is not that some people have the gift. A 2008 follow-up across 247 samples found the differences between judges were tiny, and the best judges did no better than chance alone would produce. What varied far more was the liar: some people simply come across as believable whether they are lying or not.

Who it fails, and how

It fails in two directions. The confident, friendly stranger gets through because believable people are believed. The awkward, honest seller gets turned away because nervousness looks like guilt. Neither judgement says anything about the facts.

Notice what is being traded here. Nothing has been shown, only feelings about character, offered in both directions. That exchange feels like trust and checks nothing.

Why this matters more now

The same 2006 review found people judged lies a little better when they could hear them than when they could only see them. Yet online we lean on the least useful channel: a profile photo, a face on a call, a confident tone in text.

Technology widens the gap. In a 2021 experiment, people could not reliably spot deepfake videos and still believed they could. The feeling of being able to tell has outlasted any ability to tell. More in seeing is no longer believing.

What works instead

Levine's research points to how lies actually come to light: rarely in the moment from someone's behaviour, usually later, when what was said is compared with evidence. So bring the evidence forward. Before money or safety is at stake, check the parts of the story that can be checked.

• Does the name belong to a person someone has actually verified, not just a profile they made?
• Does the thing exist? Can you see it, collect it, or pay on delivery?
• Did the money arrive? Look in your own bank app, not at a screenshot.
• Is this really the bank, the company or your cousin? Call back on a number you already have.

Keep listening to your gut, but give it a smaller job. A bad feeling is a good reason to check. A good feeling is not a reason to skip the check.

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