A recent study has shown that the handwriting of a liar changes slightly and that using a specialised computer tool to record those changes may lead to a new way for law enforcers to pick out the liars among us.
The research was done at Haifa University in Israel and will be published in an upcoming issue of the journal Applied Cognitive Psychology. The study was headed by Gil Luria and Sara Rosenblum. They used a specialised computer tool called Computerised Penmanship Evaluation Tool (ComPET). Participants wrote on the tablet and the data about their handwriting was analysed by the attached computer. The study showed that there were decipherable changes in handwriting when a person was writing the truth as compared to when they were writing a lie. The changes were found in the pressure the writer applied to the tablet and in an increase in the length and height of the stroke.
Handwriting analysis to determine a person's personality traits has long been set aside as pseudoscience, a practice presented as science but not based on scientific method, but this may no longer be the case. Already past research has confirmed that analysis of handwriting can assist in the diagnosis and progression of certain diseases including Parkinson's, Alzheimer's, schizophrenia and depression.
By the time we are adults our handwriting is almost an automatic response with very little variation in terms of stroke length and width, speed, the amount of time the pen is on the paper as opposed to being in the air, and pressure applied when writing.
Past research has also shown that lying can produce visible changes in our bodies. Lying requires more effort from our body and brains than telling the truth does. Liars tend to pay more attention to their own reactions and their own behaviours. They also pay closer attention to the interviewer's reactions to what they are saying. Liars use effort to suppress the truth and with reminding themselves of the lie. All of this requires more effort from the brain increasing the mental load.
If a person is lying and at the same time trying to write, some of their cognitive ability that would have been used for writing is taken up by the process of lying so their handwriting is altered. "It seems that in a task with higher mental load, such as writing a lie, the automatic process involved in normal handwriting is replaced with a more controlled process," the study says.
The study included 34 participants, 25 women and nine men. The computer was able to detect statistical differences when the participants were writing falsehoods.
Though this was a preliminary study and with a small sample of participants, the researchers believe that analysing handwriting in this manner to detect liars would be an excellent tool for law enforcement agencies.
The current methods of lie detection involve verbal tests, primarily using a polygraph machine. This method is quite invasive for the participant, as it requires electrodes placed around the body, unlike the handwriting test, which is more user-friendly. Also, a polygraph test has more places where human error can play a role thus making the test unreliable.