The Influence of Identification Decision and DNA Evidence on Juror Decision Making¹

Abstract

This study examined the influence of identification decision type and DNA evidence on mock jurors' ratings of evidence reliability, witness credibility, and verdict decisions. Type of identification decision was found to influence jurors' perceptions of the reliability of eyewitnesses' descriptions of various details related to the crime. Specifically, positive identifications resulted in the highest reliability ratings. Type of DNA evidence presented was found to impact on ratings of expert witness reliability. Overall, inconsistent DNA evidence that was statistical in nature resulted in the lowest reliability ratings. DNA‐consistent evidence led to more convictions than did DNA‐inconsistent evidence. Furthermore, jurors rendered more guilty verdicts when witnesses made a non‐identification or a positive identification, as compared to a foil identification.

One Country, Two Cultures

“…In the study, both eyewitness and physical evidence were found to be important factors in juror decision making, but a direct comparison between the two types of evidence showed that mock jurors were more likely to convict the defendant when they were presented with physical evidence (including matching shoeprints, and entry wounds on the deceased that matched the defendant's serrated hunting knife) than when they were presented with eyewitness testimony (positive identification by the defendant's stepmother-in-law). Although other studies similarly confirmed the high probative value of physical forms of evidence (e.g., Lieberman, Carrell, Miethe, & Krauss, 2008;Pozzulo et al, 2009), physical forms of evidence might not be as well-received among Chinese fact-finders.…”

“…The investigative method of "using the information extracted from a defendant's confession to gather further corroborating evidence" (Zhang & Shang, 2009), and slogans such as "leniency for confession and severity for resistance" (T. W. Lo, 2012) have led investigators to fall victim to the "confession complex." Although Western research has established the power of physical evidence, particularly DNA evidence (e.g., Pozzulo et al, 2009), a defendant's confession also unequivocally connects the defendant to the crime. It was predicted that participants in the present study would place a high value on confession evidence, and indeed, 70% of participants decided to convict when presented with a confession.…”

“…In Western common law jurisdictions, testimonial and scientific physical evidence are two key types of evidence that serve to establish the identity of the perpetrator and to place the accused at the scene of the crime (Pozzulo, Lemieux, Wilson, Crescini, & Girardi, 2009;Skolnick & Shaw, 2001).…”

Juror Decision Making When a Witness Makes Multiple Identification Decisions1

“…Mock jurors read a summary of a criminal trial in which one of six eyewitness ID conditions were presented: a positive ID, a non-ID, a control ID (i.e., the witness was unable to say definitively that the defendant was or was not the criminal), contradictory IDs (i.e., both a positive ID and a non-ID were presented), two positive IDs, or two non-IDs of the defendant on trial. More recent investigations have found comparable effects of the same ID manipulations (i.e., positive ID, foil ID, non-ID) on mock jurors' verdicts (Pozzulo & Dempsey, 2009;Wright, 2007), ratings of the reliability/credibility of the witness (Pozzulo, Lemieux, Wilson, Crescini, & Girardi, 2009), and the witness's ID decisions (Pozzulo & Dempsey, 2009). Mock jurors made higher guilt ratings and longer sentence recommendations when one or two witnesses made a positive ID, compared to the control ID.…”

“…Thus, it appears that both a foil ID and a non-ID were perceived as errors. More recent investigations have found comparable effects of the same ID manipulations (i.e., positive ID, foil ID, non-ID) on mock jurors' verdicts (Pozzulo & Dempsey, 2009;Wright, 2007), ratings of the reliability/credibility of the witness (Pozzulo, Lemieux, Wilson, Crescini, & Girardi, 2009), and the witness's ID decisions (Pozzulo & Dempsey, 2009).…”