Effects of false-evidence ploys and expert testimony on jurors, juries, and judges

Abstract

Triers of fact evaluated trial materials involving disputed confessions, false-evidence ploys (FEPs) during interrogation, and expert testimony. In two experiments, we assessed pre-deliberation and post-deliberation trial decisions as well as individual jurors’ perceptions, deliberating juries’ verdicts, and sitting judges’ perceptions and trial decisions. Judges convicted more often than did juries. Although triers of fact recognized the deception inherent in FEPs, the use of FEPs in police interrogations did not affect these decision-makers’ trial outcomes. Expert testimony, however, affected perceptions and reduced jurors’, deliberating juries’, and sitting judges’ likelihood of conviction. We provide recommendations for courts, scholars, and police interrogators.

Keywords:

• police interrogation and confession
• false-evidence ploys
• expert testimony
• jury deliberation
• judicial decision-making

PUBLIC INTEREST STATEMENT

In police interrogations, the use of false-evidence ploys (FEPs) – false claims to have evidence that implicates the suspect in the crime – remains legal despite experimental and archival evidence that these tactics increase the likelihood of false confessions. We evaluated triers of fact (i.e., individual jurors, deliberating juries, and sitting judges), particularly their perceptions and trial decisions related to deception during interrogation, and we also evaluated the effects of expert testimony. We found that judges were substantially more likely to convict than were juries. Additionally, although triers of fact recognized the deception and coercion present in FEPs, the precence of police deception did not affect trial decisions. Expert testimony induced skepticism in all triers of fact, leading them to be less likely to convict, but did not help them become more sensitive to police deception. Juries and judges provide only limited protections for defendants who recant their confessions after police deception.

Competing interests

The authors declare no competing interests.

Notes

1. In the ALT-key paradigm, the experimenter instructs the participant to avoid the ALT-key. The innocent suspect is then accused of pressing the forbidden ALT-key during data collection.

2. In the cheating paradigm, a participant is asked by a confederate to violate the rules of an experiment. The experimenter then accuses the participant, who may be guilty or innocent, of cheating.

3. In the individual cheating method, individual innocent participants complete a examination or game according to rules and then are accused to violating those rules.

4. The trial summary and all other materials are available from the authors.

5. We depicted the expert as highly experienced, and the expert presented testimony that was concise and not complex (see Koehler, Schweitzer, Saks, & McQuiston, 2016; Parrott, Neal, Wilson, & Brodsky, 2015). The expert’s credentials included a doctoral degree, more than 20 years of experience as a scholar of police interrogation, and numerous publications and presentations at psychology and police conventions. We held the expert’s identities and credentials constant across conditions.

6. The exact response rate is approximate due to an unknown number of misreported addresses and mail errors as well as retirements and other reasons judges may have left the bench.

Additional information

Funding

This work was supported by the Research, Dissemination, and Faculty Development Program, University of Northern Colorado [PR108].

Notes on contributors

William Douglas Woody

Professor William Douglas Woody, Professor Krista D. Forrest, Dr. Joshua M. Stewart, Dr. Skye A. Woestehoff, Ms. Karlee Rae Provenza, and their co-authors engage in experimental, meta-analytic, and historical scholarship in psychology and the law, particularly interrogation and confession, including programmatic research that investigates interrogation and confession. The research reported in this manuscript forms part of their programmatic investigations of the perceptions and decisions of individual jurors, deliberating juries, and sitting judges who must evaluate confession evidence in legal settings and according to legal requirements.