In human intelligence, a verbal statement from a source is seldom 100% true or false, and not very often is the source a total liar or a truth teller. From this standing point, a simple dichotomy of a liar or a truth teller might not offer an adequate diagnostic value for the purposes of human intelligence. A more diagnostic approach would be to assess which parts of the predominantly truthful verbal statement are likely to be true and which parts are assessed to be doubtful. In addition, the use of two parallel methods to detect deceit should improve the diagnostic value of the results. A pilot study in laboratory conditions (