Do Instructions Actually Help Jurors Evaluate Eyewitness Testimony?
Mistaken eyewitness identifications are a leading cause of wrongful convictions. Even with procedural safeguards in place (e.g., cross-examination and jury instructions), jurors still have difficulty evaluating the reliability of eyewitness identifications. In 2011, the New Jersey Supreme Court rendered a landmark decision in NJ v. Henderson in which the Court determined that, if the defendant can show evidence of suggestibility, the judge should instruct the jury on the potential impact of certain variables known to affect the accuracy of eyewitness identification. These variables are commonly categorized as either (1) system variables (e.g., biased lineup instructions or confirmatory feedback: variables that are within the control of the state) or (2) estimator variables (e.g., weapon focus or distance: variables related to the perpetrator, environment, or witness).
I am Dr. Marlee Kind Dillon, DOAR consultant and recent recipient of my Ph.D. in Forensic Psychology from John Jay College and the Graduate Center of the City University of New York. For my dissertation, I conducted two experiments in order to examine whether the judicial instructions now required by the New Jersey Supreme Court as a result of Henderson effectively sensitize jurors to eyewitness identification inaccuracy. That is, I investigated whether the instructions help jurors distinguish between accurate and inaccurate identifications.
When it comes to evaluating eyewitness testimony, jurors are required to learn and retain a lot of complex information and then apply it “correctly” to the case at hand. I hypothesized that encouraging jurors to “weigh” the conditions that enable and prevent eyewitness accuracy would lead to more complex thinking and better informed decision-making. Specifically, in any given case involving eyewitness identification, there are certain system and/or estimator variables that are at issue in the case, and thus require judicial instruction under Henderson – e.g., if the perpetrator had a weapon, the judge should instruct the jury about the weapon focus effect. To that end, I examined whether jurors who received instructions about eyewitness variables that were and were not relevant to the case (e.g., instruction on the weapon focus effect regardless of whether the perpetrator had a weapon) were more likely than those who heard only relevant instructions to make an informed verdict decision. Mock jurors were shown a video trial simulation (Study 1) or a trial transcript (Study 2), in which the judicial instructions were manipulated. System and estimator variables were also manipulated, such that they reflected either good eyewitnessing conditions (which should lead to a guilty verdict) or poor eyewitnessing conditions (which should lead to an acquittal). Following the trial, jurors completed post-trial questionnaires wherein they rendered a verdict and answered questions regarding their perceptions of each of the witnesses and the evidence.
Results of the first study did not support the Henderson court’s assumption that the instructions would help jurors evaluate the credibility of eyewitness identification. That is, while there was evidence that the manipulated variables influenced perceptions of the evidence and witnesses, there was no difference in verdict as a function of the interaction between eyewitnessing conditions and instructions. There was, however, evidence of a skepticism effect, such that jurors who heard the Henderson instructions were more likely to acquit, regardless of the quality of the identification.
The results of the second study were more promising. Jurors were most accurate in their evaluations of the eyewitness identification when they heard instructions on both good and poor conditions (as opposed to only poor conditions) and they had a chance to evaluate the impact of these variables prior to rendering a verdict. This finding supports the idea that jurors’ sensitivity to problems with eyewitness testimony may be increased by addressing both the conditions that enable and those that interfere with good eyewitness accuracy.
Overall, the results of the current studies suggest that the current Henderson instructions should be modified to improve juror sensitivity to various witnessing and identification conditions. The findings from study 2 represent a promising avenue for the future of the Henderson instructions, as they indicate we are getting closer to discovering the most effective way to instruct jurors about the reliability of eyewitness identification.