How do you know if someone is lying to you? Shifty eyes, a wavering gaze, or an inability to meet your stare are common assumptions. But according to Robert Feldman, Professor of Psychology at the University of Massachusetts, these signs are unreliable. Statistically, guessing whether someone is lying is often less accurate than flipping a coin.
Feldman has spent 25 years studying deception and authored the book Liar: The Truth About Lying. He argues that humans are inherently poor lie detectors, even with advanced technology like EEGs, thermal imaging, or MRI scans. These tools can measure brain activity or eye temperature, but they cannot specifically isolate deceptive behaviour from nervousness or concentration.
This difficulty gives liars what Feldman calls 'Liar's Advantage' – a tactical edge supported by our own gullibility. 'We don't expect to be lied to,' he explains. 'Often, people are telling us what we want to hear. The liar is trying to lie successfully and we want to believe them, so we do.'
Lying is a skill learned early in life. Studies show that children as young as three will lie to avoid breaking rules, and by age five or six they become proficient. Feldman notes that deception is an evolutionary tactic, observed even in the animal kingdom. The Portia spider, for example, mimics the vibrations of other species to lure prey, demonstrating that lying is not just human but a survival strategy across nature.
