Patent US 5,876,334

Lie detection system utilizing manual or verbal reaction time to carefully crafted questions used to discriminate between liars and truth-tellers. The invention comprises the hardware and software required to perform the response speed test as well as the questionnaire composition methodology. Discrimination between liars and truth-tellers is enhanced by asking questions requiring simple answers such as "Yes," or "No," and containing an element of surprise to force the liar to manufacture lies on the spur of the moment. His task is further complicated by adding logical inversion levels in his mind using "lying-on-command," negations and double negations. Response time variations between individuals and between questions are reduced by means of controlled questions and controlled subjects, random delays in question presentation, delays in the key word presentation and randomization of question order. Strategies for countering countermeasures of liars are based on statistical techniques, priming and assigning concurrent tasks. Advantages include: no need to wire the subject to a machine, objective assessment made by computer software with minimal input from an operator, and remote operation of the device through a telecommunication medium (modem).