Horowitz, I. A. (1988). Jury nullification: The impact of judicial instructions, arguments, and challenges on jury decision making. Law and Human Behavior, 12, 439-453.
The present study was conducted to determine the effects of nullification information to the jury from two sources, judge’s instructions and lawyers’ arguments, on juries’ verdicts and decision making in three criminal cases. In addition, the research tested the impact of challenges to nullification information on trial outcomes. The results, gathered from 144 six-person juries, indicated that when juries are in receipt of nullification information from the judge or defense attorney they are more likely to acquit a sympathetic defendant and judge a dangerous defendant more harshly than when such information is not present or when challenges are made to nullification arguments. Analysis of the juries’ decision-making processes suggested that nullification information may alter the way in which juries perceive and use the trial evidence. In those trials in which a nullification defense was successful, juries used the outcome of the case, as well as the intent of the defendant, to evaluate the worth and weight of the evidence. Pronullification conditions devalued the currency of the evidence and permitted juries to utilize nonevidentiary factors in deciding the cases used in this study.
Juries acquitted more when reminded of nullification ability by judge and with a sympathetic defendant (i.e., euthanasia, weapons) when reminded by defense, but juries convicted more with an unsympathetic defendant (i.e., DUI, homicide). Prosecutor challenge reduced impact, especially in euthanasia case. Discussion mediated effects of trial characteristics on verdicts; relationship between evidence and verdict varied across trial.