Human Lie Detector: The #1 Sign They’re Lying To You, Catch Liars Instantly! | Dr Leanne ten Brinke

Leanne ten Brinke opens by challenging the cinematic image of a psychopath as an obviously dangerous villain. She says a brief interaction may provide a “kernel” of information, citing research by Scott Lilienfeld and colleagues in which participants rated criminal offenders after five-, ten-, or twenty-second interview clips. In the study as described, novice observers' judgments after five seconds were reasonably correlated with trained clinicians' assessments based on hours-long interviews and collateral information. That result is about correlation in ratings, not proof that a five-second glance diagnoses psychopathy or reliably predicts how someone will behave in everyday life. The interview does not supply the sample size, numerical correlations, or the study's broader limitations.

Her lab's coding of those interviews points to possible behavioral cues. People with higher psychopathic-trait ratings showed more Duchenne smiles—smiles involving activation around the eyes—and more hand gestures. In some clips, a cheerful-looking expression appeared alongside hostile language. These mismatches may draw observers' attention and influence their first impression, but ten Brinke stresses that they are only a small amount of information. Even the familiar detail of crow's-feet is qualified as theoretical: Botox and other factors can affect what appears around the eyes. A cue can prompt further attention, but it cannot by itself establish a person's character.

Ten Brinke's doctoral research examined high-stakes deception in televised appeals for help finding a missing loved one. Some of the people making those appeals were later found responsible for killing the missing person; the comparison group genuinely did not know where their loved one was. She describes differences in facial expressions of sadness, including the movement of the inner eyebrows, and contrasts genuine sadness with expressions that looked more like surprise. The example shows why facial behavior may be informative in a specific, consequential context, but the passage does not establish that the same patterns apply to ordinary lies or ordinary conversations.

An early analysis combining two verbal and two nonverbal cues reportedly classified liars and truth-tellers with about 90% accuracy. Ten Brinke immediately adds an important replication caveat: a more recent attempt found much more modest effects, although some consistencies remained, especially in verbal behavior. In her examples, deceptive appeals tended to include tentative or vague instructions, while truthful speakers were more precise. The interview does not describe the sample, test conditions, or the exact replication results, so the 90% figure should be read as an early finding that did not reproduce at the same strength, not as a general-purpose lie-detection rate.

The broader lesson is not that one facial expression or mannerism exposes a liar. Ten Brinke says people often believe gaze aversion is the leading sign of lying, but she knows of no research supporting that stereotype. Instead, she points toward combinations of subtle cues and follow-up questions. A mock-theft experiment in her lab, introduced at the end of this excerpt, sets up a more direct test of how accurately people detect lies; its results have not yet been discussed in this section. Across the examples so far, her caution is that personality and deception judgments improve with more information across contexts, and no single cue functions as a “Pinocchio's nose.”