A real rape case was recorded on video, and the primary study goal was to determine the role of lay people during jury deliberations. To evaluate the precise impact of the judge on the jury, an adverse situation was created that involved a unanimous post-deliberation verdict; the verdict of the judge was in line with the minority pre-deliberation verdict, but the verdict of the judge was not rigid. After seeing the video, lay people completed a pre-deliberation questionnaire, deliberated, and then completed a post-deliberation questionnaire. Self-reports of jurors confirmed they considered the situation to be real. No one changed his or her initial vote in order to oppose the judge. In all deliberations, the judge won supporters. With the two-thirds decision rule applicable in the case, the group verdict always coincided with the judge's initial verdict. Most jurors viewed the status of the judge as superior and decisive in the group decision. Findings supported the hypothesis that, besides informational pressure, obedience and diffusion of responsibility toward the judge were underlying factors in verdict change. Jury systems in Germany, France, and Italy are briefly examined. Mathematical parameters used to study Spain's jury system are appended. 26 references and 2 tables