Irwin A. Horowitz

The effect of jury nullification instruction on verdicts and jury functioning in criminal trials

Jury nullification is a mechanism, and a defense, which allows the jury, as representatives of the community, to disregard both the law and the evidence and acquit defendants who have violated the letter, but not the spirit of the law. Should juries simply follow the law as articulated by the trial judge, or should they act as “conscience of the community,” and neglect the strict requirements of the law when it would lead to unjust or inequitable verdicts? The present study was aimed at providing empirical data for the following question: will the jury operate in a manner which is different than its normal functioning if given explicit nullification instructions? Three nullification instructins varying in explicitness as to nullification were combined with three criminal cases to yield a 3×3 factorial design. Forty-five six-person juries (270 subjects), were randomly assigned to the nine experimental groups. The results showed that juries given explicit nullification instructtions were more likely to vote guilty in a drunk driving case, but less likely to do so in a euthanasia case. The third case, which dealt with murder, did not show any differences due to instructions. Juries in receipt of nullification instructions spent less deliberation time on the evidence and more on defendant characteristics, attributions, and personal experiences.

Juror competence in civil trials: effects of preinstruction and evidence technicality

Forty-eight jury-eligible adults heard 1 of 4 versions of a tort trial. The design combined high and moderate levels of evidence technicality and the placement of substantive judicial instructions either before or after evidence presentation. Jurors given instructions before hearing the evidence for liability and before the evidence for compensation made clear distinctions among 4 differentially worthy plaintiffs, whereas jurors instructed after evidence presentation were not able to distinguish among the plaintiffs. Preinstructions enabled jurors to devise a causal model, as measured by both verbal representation of the evidence and recognition tests, that contained more probative evidence and less nonprobative and evaluative information than the models constructed by jurors who were postinstructed. Preinstructed jurors were better able than postinstructed jurors to correctly reject recognition items not part of the trial text and to correctly identify items from the trial.

A concept in search of a definition: The effects of reasonable doubt instructions on certainty of guilt standards and jury verdicts

Eighty (6-person) juries heard 1 of the 5 reasonable doubt instructions in a trial that either had strong evidence for guilt or favored acquittal. None of the instructions produced acceptable criteria of self-reported reasonable doubt, although instructions that informed juries to be firmly convinced (FC) elicited the highest standards of proof. The FC instructions yielded verdicts that tended to correspond with the evidence in both versions of the trial. FC juries focused proportionately more on the evidence and less on non-probative issues than juries given other instructions. Juries had lower self-reported standards of proof when the trial evidence was weak for conviction as opposed to when it was strong. The discussion addresses the surprisingly low self-reported standards of proof.

Nominal and Interactive Groups: Effects of Preinstruction and Deliberations on Decisions and Evidence Recall in Complex Trials

Two studies assessed the effects of preinstruction on decision making in simulated civil trials. In Study 1, substantive instructions were presented before the evidence, after the evidence, before and after the evidence, or not at all to nominal jurors who did not deliberate and to interactive jurors who did deliberate. Preinstructed nominal jurors differentiated among the plaintiffs in awarding damages, whereas postinstructed nominal and interactive jurors did not. Group discussion and preinstruction augmented damage awards and improved recall of evidence only for preinstructed jurors. Study 2 suggested that substantive preinstruction engaged a proplaintiff bias when trial evidence was technically difficult but enhanced systematic processing when the evidence was presented in less complex language.

Enhancing Juror Competence in a Complex Trial

This study examined the effects of providing substantive, case-related, judicial instructions before presentation of evidence and permitting jurors to take notes, on verdicts and cognitive performance in a complex civil trial. Jurors made compensatory awards when the evidence either strongly or modestly favored the plaintiffs. One hundred and twenty jury-eligible participants saw a videotape of a cognitively dense trial involving multiple plaintiffs. Notetakers, while showing superior cognitive performance over non-notetakers, were more effective decision makers when pre-instructed and facing less ambiguous evidence. Results indicated that notetaking when jurors are pre-instructed enhanced recall of probative evidence and resulted in fewer non-probabitive intrusions, which facilitated decision making on legally appropriate grounds.

The effects of outlier presence, plaintiff population size, and aggregation of plaintiffs on simulated civil jury decisions

An experiment was performed to determine the effects of the size of the plaintiff population, the presence or absence of an outlier, defined as a plaintiff whose injuries were significantly more severe than other plaintiffs, and whether plaintiffs were tried individually or were aggregated in a group. Sixty-six person juries were assigned to one of eleven experimental conditions, listened to a 4-h toxic tort tria, and after deliberating, delivered verdicts on liability, and damage awards. The verdicts were increased significantly by the presence of an outlier and by an increase in the plaintiff population. While the punitive awards were higher in the outlier condition, there was also a tendency for juries to find the company not liable.The meaning of the above findings, as well as the fact that juries exhibited great variability in their verdicts was discussed. Evidence as to the decision-making process of the juries was also gathered and discussed.

Effects of notetaking on verdicts and evidence processing in a civil trial

Examined the effect of notetaking on juror decision making and cognitive processing of evidence in a complex tort trial. Jury eligible participants either took notes during the trial and had access to those notes during decision making, took notes without access, or did not take notes. Those who took notes during the trial performed more competently than did nonnotetakers. Notetakers made correct distinctions in assigning liability and compensatory awards among four differentially worthy plaintiffs and recalled significantly more probative evidence than nonnotetakers. The almost identical performance of the notes-access group and the notes without access group suggests that notetaking had its impact at the encoding stage rather than at retrieval. We discuss possible motivational differences that may account for the results and constraints on generalizing the findings.

Informing Jurors of Their Nullification Power: A Route to a Just Verdict or Judicial Chaos?

The current studies sought to test whether explicitly informing jurors of their power to nullify the law does invite “chaos,” defined by jurists as undisciplined and biased juror judgment. A series of four studies examined juror biases predicated on defendant status, remorse, gender, national origin, penalty severity, and extenuating circumstances. None, however, were amplified by nullification instructions, providing little evidence that such instructions invite chaos with respect to the biases examined in these studies. To the contrary, several results suggested that nullification instructions simply encourage jurors to nullify when the strict application of the law would result in an unjust verdict. Limitations of the studies and public policy issues are discussed.

The effects of jury size, evidence complexity, and note taking on jury process and performance in a civil trial.

A total of 567 jury-eligible men and women who were assigned to 6- or 12-person juries saw a videotaped civil trial that contained either I or 4 plaintiffs. Half the juries took notes, whereas the remainder did not. Six-person juries that did not take notes awarded multiple plaintiffs the highest amounts of compensation. Six-person juries also gave the highest punitive damages when they did not take notes and judged multiple plaintiffs. The punitive awards of 6-person juries were highly variable compared with 12-person juries. Multiple plaintiffs also increased the unpredictability of jury punitive awards. Twelve-person juries deliberated longer, recalled more probative information, and relied less than 6-person juries on evaluative statements and nonprobative evidence. Limitations and implications are discussed.

Effects of Technicality and Access to Trial Transcripts on Verdicts and Information Processing in a Civil Trial

Two studies assessed the effects of evidence technicality on judgments and evidence processing in a civil trial. In Study 1, 48 jury-eligible adults heard a medical malpractice case that was either high or low in technicality of evidence and were or were not given access to a verbatim trial transcript while reaching a verdict. The evidence of the trial favored the defendant. However, jurors unable to process systematically were expected to employ a readily available counterfactual heuristic and to decide for the plaintiff. In Study 2, 64 college students heard the same trial either high or low in technicality and with or without closing arguments that blocked the use of the counterfactual heuristic. In both studies, low evidence technicality led jurors to process the evidence systematically and to decide for the defendant. Access to transcripts and blocking of counterfactual reasoning led to increases in decisions for the defendant under high evidence complexity.