Does the structure of the evidence base “cause” verdicts of guilty and innocent?
Michael P. Ryan, Richard R. Hurtig · Discourse Processes · 1980
The analysis of juror cognition requires a distinction between evidence comprehension and verdict computation. Some investigators have assumed that verdict choice depends upon properties of the evidence base rather than upon the outcome of the application of a verdict algorithm to that evidence base. The evidence bases developed by eight members of a guilty‐verdict group and six members of an innocent‐verdict group for a medical malpractice case were compared using multidimensional scaling procedures. INDSCAL and HICLUS solutions for the relatedness rankings of twelve evidence elements for the two groups of undergraduates were virtually indistinguishable at an initial session and one four days later. No dimension of the two‐ or three‐dimensional INDSCAL solutions was differentially salient for members of the guilty‐verdict group. Verdict‐related differences between these mock jurors only emerged in response to instructions at the second session to simulate the evidence base of members of the opposite verdict group. These data imply that jurors arriving at different verdict conclusions differ in the way they compute verdicts from a common evidence base rather than in the structure of their evidence bases. Some limitations of these findings are considered, and it is concluded that the legal system's distinction between evidence comprehension and verdict deliberation is a defensible one.