Experimental Study On The Influence Of Cognitive Load To Comparisons Question Test

Polygraph test plays a more and more important role in the related areas as a majot assistant method in judicialinvestigation. And the scientificity and veracity of this technology are always concerned by the researchers in this field. CQT as the most common use method of Polygraph, to research and improve it will be helpul for making CQT play a bigger role and get more extensive support and acceptance. This research study the type of test questions and the content of the comparison questions in CQT. By increasing the cognitive load during the test, the test result is influenced. In the traditional CQT, the test question is used to be the general question, and the subjects just need to tell "yes" or "no". Furthermore, the content of comparison question is about the experiences or thoughts that the subject unwilling to talk about, the relationship with the case itself is hard to distinguish. In this research, the type of test question is changed to be general question and special question appearing alternately and the content of comparison question is the recalling of the scene. According to the changes ablove, it increases the cognitive load of the subjects during test process. The whole dissertation included six parts:The first is the literature review part. In this part, it talks the theoretical basis and study development of deception detection, and further expounds the comparion question test which is the focus of this study. After this, it presents the theories and researches of cognitive load that related to deception detection. The second part sums up the issues existing in literature review, and brings forward the significances and hypothesis of this study.The third part consisted of three studies. The first study uses Biofeedback instrument to investigate the influence of recalling order and sentence pattern to subjects’ physiological indexs. The result shows that the change of recalling order and sentence pattern could adjust subjects’ cognitive load in the Q&A process, and in such a condition of2kinds of sentence pattern and reverse memory, the change rate of subjects’ physiological indexs will increase with the increase of their cognitive load. Based on the result of the first study, the second study makes a improvement on the traditional CQT questions by increasing subjects’cognitive load in the test process to improve the accuracy of the test. The result shows that the improved test will expand the difference between the honests and the liars, and make the test result more accurate.The third study is a further research of the second. It compares the test results of traditional and improved tests in three problem situations:the existing of reactance, the interval time difference and the case severity difference. The result shows that improved test could reduce the impacts of reactance to the test accuracy; after a relative long interval time, compared to the tradional test, improved test will get a better result; and nomatter how the case severity is, the result of improved test will be more satisfying.The part four and five discuss ad analyze the results of the whole three studys, and summarize the main research conclusions. The last part lists the innovations and limits of this study, and brings forward the assumes of the further study.