Comparing the efficacy of expert testimony and detailed juror instructions under high and low cognitive load.

I investigated juror's ability to update knowledge following clarifying information about eyewitness memory. In Experiment 1, mock jurors read a trial summary describing the armed robbery of a convenience store and included eyewitness testimony, and rendered a verdict. Jurors then read the New Jersey "Henderson" juror instructions, watched or read the testimony of a memory expert, or read about an unrelated topic, and rendered a verdict. Jurors who received information regarding eyewitness memory (juror instructions or expert testimony) were more confident in a not guilty verdict at Time 2, indicating mock jurors were able to process initial information and make changes when new information becomes available. Need for cognition played a unique role in the decision making process. In Experiment 2, jurors performed the same task under conditions of high or low cognitive load. Jurors who did not receive clarifying eyewitness memory information did not change verdict confidence over time. Jurors under low load were more confident in a not guilty verdict following clarifying memory information. However, mock jurors under high load did not change verdict confidence at Time 2, indicating jurors' ability to process clarifying memory-related information was impaired under conditions of high cognitive load. Implications of juror decision making under cognitive load are discussed.