Inadmissible Testimony, Instructions to Disregard, and the Jury: Substantive Versus Procedural Considerations

The present study tested the hypothesis that jurors comply selectively with instructions to disregard inadmissible evidence. A total of 81 mock jurors read a murder trial summary in which a wiretap was ruled admissible, inadmissible because it was not reliable, or inadmissible because it was illegally obtained (there was also a no-wiretap control group). As predicted, participants were more likely to vote guilty and interpret subsequent evidence as more incriminating in the admissible and inadmissible/due-process conditions than in the admissible/unreliable and control groups. These results suggest that jurors are influenced not by the judge's ruling per se but by the causal basis for that ruling. Conceptual and practical implications are discussed.