Do jurors share a common understanding concerning eyewitness behavior?

It would seem that the American judiciary have traditionally viewed knowledge of variables affecting eyewitness behavior as a part of common understanding. The presumption would then be that there is a body of knowledge in this regard that is indeed shared and that this shared understanding conforms substantially to objective reality. Multiple-choice format questionnaires designed to tap such knowledge were administered to two somewhat disparate samples of college students (n=176) and two samples of the citizenry at large in Washington D.C., 46 of whom had not had criminal trial jury experience in the previous five years and 43 of whom had. Across samples the typical respondent's performance was significantly above chance but not at all high in absolute terms. This typical performance involved well above chance levels of accuracy on about half the items and not different from chance accuracy on the others. At least within the college student samples, certain demographic variables were not related to accuracy of response. Likewise, previous criminal trial jury experience did not improve accuracy for the Washington D.C. respondents by an amount that would be practically significant. It was concluded that the common understanding doctrine cannot in general be supported.