Judicial instructions and the juror's ability to disregard inadmissible evidence: Can varying the timing and content of judicial instructions influence juror decision-making

During the course of a trial, a judge will instruct the jury on how they are to act and reach decisions. The purpose of this study was to examine the effect of different judicial instructions on a juror's ability to evaluate testimony. The research looked at how instructions can interact with a juror's ability to disregard a piece of evidence ruled inadmissible for different reasons. The design was a 3x5 complete factorial design. The stimulus material was a murder trial summary with weak evidence against the defendant, with the key piece of testimony being a hair found on the victim that matches the defendant. This evidence was objected to and admitted or not admitted into evidence depending on the condition. The hypotheses test how a juror's decision-making process is influenced by a combination of judicial instructions, including one designed to raise suspicion, the ruling -- admitted or not admitted, and the reason behind the ruling.