Trivial persuasion in the courtroom: The power of (a few) minor details.

TLDR

The study examined how trivial testimonial details affect mock jurors’ guilt judgments. Participants read a summary of a robbery‑and‑murder case. Detailed testimony increased guilt judgments, especially when an opposing witness could not recall details, and this effect was mediated by perceptions of eyewitness credibility, memory, and attention.

Abstract

Investigated the influence of trivial testimonial detail on judgments of 424 undergraduates who served as mock jurors. Ss read a summary of a court case involving robbery and murder. In Experiment 1, detailed testimony influenced judgments of guilt, even when the detail was unrelated to the culprit. In Experiment 2, detailed testimony was especially powerful when an opposing witness testified that she could not remember the trivial details. Subsequent analyses suggest that the impact of detailed testimony on guilt judgments is mediated by inferences about the eyewitnesses. When eyewitnesses provided more detail, they were generally judged to be more credible, to have a better memory for the culprit's face and for details, and to have paid more attention to the culprit.