Wilson Center researchers recently joined Nicholas Scurich, Associate Professor of Criminology, Law & Society, Vice Chair of the Department of Psychological Science at the University of California in Irvine, to explain their findings about lay jurors perceptions of forensic evidence.
Wilson Center Director Brandon Garrett and Research Director Dr. William Crozier described two experiments as part of a presentation hosted by the Center for Statistics and Applications in Forensic Evidence (CSAFE). CSAFE is a funder of the Wilson Center.
In the first experiment, researchers 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. The second involved testimony about firearms evidence. They tested whether ostensibly more cautious language had its intended effect on jurors, and whether cross-examination impacts jurors’ perception of firearm testimony.
“Human decision making is kind of at the core of a lot of forensic disciplines,” Crozier explained.
He walked through how blind proficiency testing works, and how researchers try approaches to get the most accurate replication of a test as possible.
“Obviously, there is a lot of benefits to measuring performance using blind proficiency tests; what we don’t know is how jurors view this information,” he said. “Do they pick up that this is a best practice? Does blind performance change their view of the examiner or of the evidence or change their verdicts in a case?”
The researchers’ findings support the view that additional blind proficiency testing programs, in addition to their quality control benefits, do not prejudice jurors.
In the firearms part of the study, researchers 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.
“Based on the data from this study … it’s just not enough to cross examine experts, firearm experts, on the stand,” Scurich said.
You can watch the entire presentation below, and read the article here.