While most are familiar with the story of Pinocchio, the puppet boy whose nose grows when he tells a lie, scientists at the University of Granada say people's noses actually shrink when they fib.
In fact, two physiological effects happen when people lie that are so observable, the researchers say they could make for the "world's most reliable lie detector," the Daily Mail reports.
Study lead author Dr. Emilio Gómez Milán gives the, er, long and the short of it: "One has to think in order to lie, which rises the temperature of the forehead. At the same time we feel anxious, which lowers the temperature of the nose."
Less blood flow to the nose causes it to cool, and shrink.
This disparity, which can be detected with heat-sensing cameras, can flag a fibber 80% of the time, according to Gomez Milán's team -- far better than the modern polygraph machines.