A computerized system developed by Israeli scientists can detect if people are lying, just by analyzing their handwriting.

When you tell a lie, you don’t just give yourself away with your voice, but with your writing too, according to new research by Israeli scientists.

Researchers at the University of Haifa have discovered that when we write a falsehood the pressure of our pen, the duration of time when the pen is on and off the page, and even the flow of our writing, changes – and that these alterations can be detected by a computerized writing-analysis system.

“It seems that the act of writing a false text involves extensive cognitive resources and the automatic act of writing is thereby affected,” says Dr. Gil Luria of the university’s Department of Human Services who carried out the research with Dr. Sara Rosenblum of the Department of Occupational Therapy.

Identifying a lie is a difficult and complex task. The tools available today, such as the polygraph, which is widely used by police and security forces worldwide, are still problematic and not always accurate.

Writing lies affects performance

While the polygraph attempts to identify physiological changes, such as changes in heartbeat, blood pressure and respiration, the current study has examined whether the act of lying causes cognitive changes. This approach is based on the assumption that lying – writing lies in this case – requires special resources and causes cognitive stress, which in turn affects performance that would otherwise be executed automatically.

The participants in the study were asked to write two paragraphs. First they were told to describe an event that really took place and then to give a description of an event that had not really occurred.

The texts were written with an electronic pen on a page that was placed on an electronic board. The data was analyzed with the help of a computerized writing-analysis program that Rosenblum developed a few years ago. The system is able to garner data that cannot be measured manually, such as pressure, rhythm and speed, duration and frequency.

The researchers found that various cognitive characteristics in written falsehoods are different from those that appear in truthful writing. The study found that pressure on the page when writing deceptive content is significantly heavier than when writing the truth. Likewise, the flow of strokes when writing false text, as expressed in the height and length of the letters, is different from these elements in truthful writing.

Improving our ability to get to the truth

According to the researchers, the results of the study show that when writing a lie, otherwise automatic acts become more controlled by the brain and consequently performance is altered, which is shown in the size, duration and pressure of the false writing.

“A lie detector that analyzes 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 researchers said.

“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,” they concluded.