POLYGRAPH TESTIMONY AND JUROR JUDGMENTS - A COMPARISON OF THE GUILTY KNOWLEDGE TEST AND THE CONTROL QUESTION TEST

The present experiment investigated the impact of the Control Question Test (CQT) and the Guilty Knowledge Test (GKT) on the verdicts of moc k jurors. Although studies have indicated that polygraph evidence has little influence on jurors' verdicts (Cavoukian & Heselgrave, 1980; Sp anos, Myers, Dubreuil, & Pawlak, 1992-1993), no research has previousl y distinguished between the different types of polygraph tests and the ir impact on juror verdicts. In the present study, jurors were shown a videotape of a simulated rape-murder trial that contained either CQT polygraph evidence, GKT polygraph evidence, or no polygraph evidence. No differences were found among the 3 conditions for either jury verdi cts or individual juror verdicts, and jurors tended to rate both forms of polygraph polygraph testimony below other forms of equally suspect evidence, such as eyewitness testimony, in its influence on their dec ision-making process.