Recording of webinar is available.
We will describe two recent experiments. In the first, we conducted two studies whether knowledge of an expert’s performance on blind proficiency testing affects trust in the expert witness, the evidence (fingerprint or bitemark), and verdicts. We also examined whether cross-examination affected these outcomes. As labs consider adopting blind proficiency testing programs, we wanted to better understand how information about those programs impacts jurors. Our results support the view that additional blind proficiency testing programs, in addition to their quality control benefits, do not prejudice jurors.
Second, firearms experts traditionally have testified that a weapon leaves “unique” toolmarks, so bullets or cartridge casings can be visually examined and conclusively matched to a particular firearm. Recently, due to scientific critiques, Department of Justice policy, and judges’ rulings, firearms experts have tempered their conclusions. In two experiments, we tested whether this ostensibly more cautious language has its intended effect on jurors (Experiment 1), and whether cross-examination impacts jurors’ perception of firearm testimony (Experiment 2). We found that apart from the most limited language (“cannot exclude the defendant’s gun”), judicial intervention to limit firearms conclusion language is not likely to produce its intended effect. Moreover, cross-examination does not appear to affect perceptions or individual juror verdicts.