To Catch a Liar, Stop Looking at Them

Everything you think you know about catching a liar is wrong, and your eyes are why.

Researchers at the University of Portsmouth put 120 people in the role of interviewer and split them into two groups: one watched video of a mock suspect, one heard only the audio. Overall accuracy in distinguishing truths from lies for the audio-only group was nearly double that of the video group, 61.7 percent versus 35 percent.

The culprit, the researchers argue, is cognitive load. The study, published in The European Journal of Psychology Applied to Legal Context, examined how the interviewer's cognitive load (how hard the brain is working) influences performance and interview outcome. The short version: when you're busy processing a face, your working memory doesn't have much left over for the actual words coming out of that face. Access to visual cues made interviewers more likely to suspect deception and impaired their ability to assess veracity.

What does work? Accuracy was positively associated with verbal cues (specifically, the quantity of details in accounts) and vocal cues (specifically, speech disturbances) rather than visual behavioral indicators. The lies are in the hesitations, the thin details, the places where a story stops being specific. The shifty eyes are decoys.

"This has important implications for training programmes, which often emphasise reading body language and facial expressions," noted lead author Dora Giorgianni. Which is a polite way of saying that decades of interviewer training may have been teaching people to do exactly the wrong thing.

The face is very convincing. It just isn't particularly informative.

Read the full story at Nazology, May 14, 2025

Hot Take: Every law enforcement training manual that opens with a chapter on reading micro-expressions is essentially a guide to being confidently wrong.