People who are writing lies press harder on the paper and produce taller letters than those who are telling the truth, according to Israeli scientists who have developed a handwriting analysis system.
The system, developed by the Faculty of Social Welfare and Health Sciences at the University of Haifa, measures differences in pressure on the page, duration of the pen on and off the page and the flow of writing.
“It seems that the act of writing a false text involves extensive cognitive resources and the automatic act of writing is thereby affected,” explain the researchers.
Despite its popularity in sleazy chat shows, the polygraph has always been an unreliable tool. But while the polygraph is supposed to identify physiological changes during the act of lying, the Haifa study looked at whether lying causes cognitive changes. The idea is based on the assumption that lying requires special resources and causes cognitive stress, which in turn affects performance.
The participants were asked to write two paragraphs, first describing an event that really took place and then one that did not really occur. They wrote the paragraphs with an electronic pen on a page placed on an electronic board.Pressure, rhythm and speed, duration and frequency were then analyzed
The study showed that pressure on the page was significantly heavier when lying, and that the flow of strokes, as expressed in the height and length of the letter s, was distinctly different. According to the researchers, this shows that when writing a lie, acts that are usually automatic become more controlled by the brain and performance is altered, showing up in the size, duration and pressure of the false writing.
“A lie detector that analyses handwriting has many advantages over the existing detectors, since it is less threatening for the person being examined, is much more objective and does not depend on human interpretation. The system also provides measures that the individual has difficulty controlling during performance. This is certainly a system that can improve – alongside the existing detectors – our ability to identify lies,” the researchers concluded.