People make awful lie detectors. We all think we can tell when somebody is lying to us, but scientists have proven otherwise again and again. Researchers Michael Lewis and Carolyn Saarni left a group of five-year-olds in a room with their favorite toy and told the children not look at it. The experimenters left the room and came back after a few minutes. Hidden cameras revealed that 85% of the children looked at the toy, but only 38% of them admitted to doing so. Lewis and Saarni showed the kids’ parents videos of their children saying whether or not they’d looked at the toy. The researchers asked the parents to judge whether their kids were lying or telling the truth. The parents were right half the time—no better than chance would indicate

In another study, scientists showed participants a photograph of an extremely attractive person of the opposite sex. The scientists asked the subjects to convince their significant others that they found the model unattractive. Then the scientists asked the subjects’ significant others whether the subjects were lying or telling the truth. The significant others were right less than half the time. In a related study, University of California psychologist Paul Ekman showed videos of people either lying or telling the truth to professionals known for their ostensible truth-detecting abilities (polygraph operators, robbery investigators, judges, and psychiatrists). Ekman asked the professionals to identify who was lying and who was telling the truth. The pros couldn’t beat the coin flip test either.