The effect of confession evidence on jurors' verdict decisions: A systematic review and meta-analysis

Over the past 4 decades, discrepant research findings have emerged in the juror-confession literature, prompting the need for a systematic review and meta-analysis that assesses the effect of confession evidence (coerced or noncoerced) on conviction rates and the efficacy of trial safeguards.

We did not predict any directional hypotheses. Some studies show increased convictions when a confession is present (vs. not), regardless of whether that confession was coerced; other studies demonstrate that jurors are able to discount coerced confessions. Studies have also demonstrated sensitivity effects (safeguards aided jurors in making appropriate decisions), skepticism effects (safeguards led jurors to indiscriminately disregard confession evidence), or null effects with regard to expert testimony and jury instructions.

We identified 83 independent samples (N = 24,860) that met our meta-analytic inclusion criteria. Using extracted Hedges' g effect sizes, we conducted both network meta-analysis and metaregression to address key research questions.

Coerced and noncoerced confessions (vs. no confession) increased convictions (network gs = 0.34 and 0.70, respectively), yet coerced (vs. noncoerced) confessions reduced convictions (network g = -0.36). When jury instructions were employed (vs. not), convictions in coerced confession cases were reduced (this difference did not emerge for noncoerced confessions; a sensitivity effect). Expert testimony, however, reduced conviction likelihood regardless of whether a confession was coerced (a skepticism effect).

Confession evidence is persuasive, and although jurors appear to recognize the detrimental effect of coercive interrogation methods on confession reliability, they do not fully discount unreliable confessions. Educational safeguards are therefore needed, but more research is encouraged to identify the most effective forms of jury instructions and expert testimony. One potential reform could be in the interrogation room itself, as science-based interviewing approaches could provide jurors with more reliable defendant statement evidence that assists them in reaching appropriate verdict decisions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).