10-second trick to spot liars, according to a psychopathy researcher

March 12, 2026 - 18:11

In the complex world of human interaction, discerning truth from falsehood can feel daunting. However, new insight from the study of dark personalities offers a surprisingly swift technique. According to psychologist Leanne ten Brinke, who researches psychopathy and deception, the key may lie in a simple, ten-second observation of a person's emotional expression.

The method focuses on the authenticity of emotional displays. Dr. ten Brinke suggests that genuine, synchronous emotions typically appear and fade smoothly. In contrast, a liar's emotional mask—especially when feigning positive feelings like sympathy or joy—often appears too sudden, is held too long, and vanishes abruptly. This mismatch between the emotion and the context of the conversation can be a powerful red flag.

This brief window into incongruent behavior is rooted in the difficulty of perfectly fabricating the nuanced, involuntary micro-expressions that accompany real feelings. While not a foolproof lie detector, this quick check for emotional harmony or discord provides a practical tool for anyone navigating negotiations, important conversations, or simply seeking a deeper understanding of the social dynamics at play. It underscores that often, the truth is not just in the words we hear, but in the fleeting, unguarded moments that flash across a face.