The Effect of Complexity of Expert Testimony and the Presence of a Defensive Rebuttal on Jurors’ Decisions in Criminal Trials

Faculty Mentor

Amy Hackney

Location

Russell Union Ballroom

Type of Research

On-going

Session Format

Poster Presentation

College

College of Behavioral & Social Sciences

Department

Psychology

Abstract

This study examines how the complexity of expert testimony and the presence of a defensive rebuttal affect jurors' decisions in criminal trials.  Forensic science plays a crucial role in jury verdicts, but numerous cases have resulted in false convictions due to faulty forensic techniques and that expert testimonies can be unreliable and subjective.  When forensic evidence is complex and presented without a rebuttal, jurors may rely on heuristic processing, determining the credibility of the witness based on their characteristics instead of the validity of the testimony.  Using a 2 (testimony complexity: complex v. simple) x 2 (defensive rebuttal: present v. absent) factorial design, participants read trial transcripts adapted from a real case in which faulty bite mark analysis was used to falsely convict the defendant.  The dependent variables are evidence judgement, confidence in verdict, and witness credibility.  It is hypothesized that participants who receive faulty forensic expert testimony with a lower level of complexity (simple language testimony) and the presence of a defense rebuttal will decrease the confidence in the prosecution's evidence, increase the likelihood of a correct not guilty verdict, and decrease the perceived credibility of the prosecution's expert witness.  It is additionally hypothesized that faulty forensic expert testimony delivered with high language complexity and no defense rebuttal will lead to higher confidence in the prosecution's evidence, an increase in (unjust) guilty verdicts, and higher perceived credibility of the prosecution's expert witness.  Data analysis is in progress and will be completed by the symposium.

Program Description

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Start Date

4-23-2026 2:00 PM

End Date

4-23-2026 4:00 PM

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Apr 23rd, 2:00 PM Apr 23rd, 4:00 PM

The Effect of Complexity of Expert Testimony and the Presence of a Defensive Rebuttal on Jurors’ Decisions in Criminal Trials

Russell Union Ballroom

This study examines how the complexity of expert testimony and the presence of a defensive rebuttal affect jurors' decisions in criminal trials.  Forensic science plays a crucial role in jury verdicts, but numerous cases have resulted in false convictions due to faulty forensic techniques and that expert testimonies can be unreliable and subjective.  When forensic evidence is complex and presented without a rebuttal, jurors may rely on heuristic processing, determining the credibility of the witness based on their characteristics instead of the validity of the testimony.  Using a 2 (testimony complexity: complex v. simple) x 2 (defensive rebuttal: present v. absent) factorial design, participants read trial transcripts adapted from a real case in which faulty bite mark analysis was used to falsely convict the defendant.  The dependent variables are evidence judgement, confidence in verdict, and witness credibility.  It is hypothesized that participants who receive faulty forensic expert testimony with a lower level of complexity (simple language testimony) and the presence of a defense rebuttal will decrease the confidence in the prosecution's evidence, increase the likelihood of a correct not guilty verdict, and decrease the perceived credibility of the prosecution's expert witness.  It is additionally hypothesized that faulty forensic expert testimony delivered with high language complexity and no defense rebuttal will lead to higher confidence in the prosecution's evidence, an increase in (unjust) guilty verdicts, and higher perceived credibility of the prosecution's expert witness.  Data analysis is in progress and will be completed by the symposium.