Hypothetical Courtroom: Influence of Expert Witness Testimony on Jurors’ Decision-Making
Location
Room 232, Schewel Hall
Access Type
Open Access
Presentation Type
Oral presentation
Entry Number
108
Start Date
4-16-2026 9:45 AM
End Date
4-16-2026 10:00 AM
School
School of Liberal Arts and Sciences
Department
Psychology
Keywords
juror decision-making, psychopathy, expert witness credibility, neuroscientific evidence, artificial intelligence, bias
Abstract
Jurors’ decision-making is shaped by social and psychological factors that may create bias, particularly in cases involving psychopathic defendants. The present study examined how a hypothetical defendant’s perceived psychopathy, the type of scientific evidence presented (neuroimaging vs. only verbal descriptions), the gender of the expert witness, and the expert’s use of artificial intelligence (AI) affect jurors’ decisions. Participants read one of four mock trial vignettes involving a psychopathic defendant and then evaluated the defendant’s guilt, recommended sentence length, and the credibility of the expert witness. Results indicated that confidence in the expert significantly decreased after participants were informed that the expert had used AI. A significant main effect of evidence type suggested that participants in the neuroimaging condition perceived the defendant as lower in psychopathic traits compared to those in the verbal description only condition. No significant main effects were found for expert gender or sentencing severity in the factorial analyses. However, perceptions of psychopathic traits were positively correlated with sentencing recommendations, guilt perceptions, and confidence in the expert witness. Participants who perceived the defendant as higher in psychopathy recommended harsher sentences and expressed greater confidence in the expert. These findings exemplify the complex influence of technological disclosure, biases, and character-based judgments in juror decision-making.
Primary Faculty Mentor(s)
Dr. Alisha Marciano
Primary Faculty Mentor(s) Department
Psychology
Additional Faculty Mentor(s)
Dr. Christopher Neale Dr. Paul McClure
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A 10-12 minute presentation on my study on the factors of the courtroom that influence jurors' decision-making.
Hypothetical Courtroom: Influence of Expert Witness Testimony on Jurors’ Decision-Making
Room 232, Schewel Hall
Jurors’ decision-making is shaped by social and psychological factors that may create bias, particularly in cases involving psychopathic defendants. The present study examined how a hypothetical defendant’s perceived psychopathy, the type of scientific evidence presented (neuroimaging vs. only verbal descriptions), the gender of the expert witness, and the expert’s use of artificial intelligence (AI) affect jurors’ decisions. Participants read one of four mock trial vignettes involving a psychopathic defendant and then evaluated the defendant’s guilt, recommended sentence length, and the credibility of the expert witness. Results indicated that confidence in the expert significantly decreased after participants were informed that the expert had used AI. A significant main effect of evidence type suggested that participants in the neuroimaging condition perceived the defendant as lower in psychopathic traits compared to those in the verbal description only condition. No significant main effects were found for expert gender or sentencing severity in the factorial analyses. However, perceptions of psychopathic traits were positively correlated with sentencing recommendations, guilt perceptions, and confidence in the expert witness. Participants who perceived the defendant as higher in psychopathy recommended harsher sentences and expressed greater confidence in the expert. These findings exemplify the complex influence of technological disclosure, biases, and character-based judgments in juror decision-making.