Misinformation about eyewitness confidence can influence jurors’ memories and decision making
Eyewitness testimony is often enormously influential to jurors in a trial. One aspect of that testimony, eyewitness confidence, is especially dominant in determining whether the testimony is judged as credible or not. Therefore, there has been an immense focus on proper collection and protection of eyewitness evidence. However, appropriate use of this evidence requires the jurors to accurately remember the eyewitness testimony as they are deliberating and arriving at their verdict. The current research examines the effect of misinformation about an eyewitness after they have testified, introduced during jury deliberation or closing arguments. In Study 1, misinformation about the eyewitness confidence is divulged by a juror during jury deliberation – either mistakenly stating that the eyewitness was more or less confident than was stated in trial. In Study 2, the high confidence misinformation item is disclosed either by a juror during deliberation or by the prosecutor during closing arguments. In a third condition, the prosecutor states the misinformation item, and later, during jury deliberation, a juror challenges the misinformation. In Study 3, the use of a case vignette manipulating the eyewitness confidence statement allows exploration of how jurors perceive commonly used verbal confidence statements, and how these statements influence jury decision-making. The current studies explore potential drawbacks to the use of verbal confidence statements in the criminal justice system, and seek to provide understanding toward how these confidence statements may be perceived. In Study 1, participants exposed to high confidence misinformation remembered the witness as being significantly more confident comparted to participants who were exposed to low confidence misinformation. This misinformation exposure seemed to not influence other perceptions and decision making, though. In Study 2, there was no effect of misinformation on remembered witness confidence – those who were exposed to high confidence misinformation via either a juror or prosecutor did not differ in remembered witness confidence compared to the control group. However, when a juror challenged the prosecutor for introducing misinformation, participants showed a decrease in remembered witness confidence as well as a decrease in the proportion of guilty verdicts, in comparison to participants who were exposed to misinformation from the prosecutor without it being challenged. Finally, Study 3 explored how jurors perceive commonly used verbal confidence statements. These results revealed that the eyewitness confidence statement affects how jurors perceive the witness’s accuracy, credibility, and quality of view, as well as jurors’ decision making in the case. Implications for potential consequences associated with the use of verbal statements of eyewitness confidence are discussed.