The Presumption of Innocence in the Trial Setting

Abstract

The starting frame with which jurors begin trials and the approach which they should take toward the presentation of evidence by the prosecution and defense are distinguished. A robust interpretation of the starting frame, according to which jurors should begin trials by presuming the material innocence of defendants, is defended. Alternative starting frames which are less defendantfriendly are shown to cohere less well with the notion that criminal trials should constitute stern tests of the government's case against those it has charged with crimes. The intuitive case for the robust presumption of innocence is supplemented with empirical evidence concerning the psychology of belief formation and preservation. Various objections to the proposed starting frame are addressed.

The effect of ambiguous question wording on jurors’ presumption of innocence

“…The literal mathematical interpretation of a 0% probability of guilt (or 100% probability of innocence) is that no amount of evidence can change the probability of guilt/innocence (i.e., the outcome of the trial is certain from the start). This is not consistent with mainstream interpretations of the presumption of innocence, which require the probability of guilt to be low, but not zero (Allen et al, 1994;Dahlman, 2017;Lippke, 2015). However, given our data it is not clear if participants providing 0 or 100 responses fully appreciated the literal mathematical meaning of these choices.…”

“…Specifically, 78.9% of participants believed the law instructs them to adopt a 100% probability of innocence at the beginning of a trial. This was not the case for the factual or ambiguous wording, and is not consistent with widely accepted interpretations of the presumption of innocence (Allen et al, 1994;Dahlman, 2017;Lippke, 2015). We will return to this issue.…”

“…Most legal scholars contend that the presumption of innocence directs jurors to regard the initial probability of the prosecution's hypothesis as low, but not zero (Allen, Balding, Donnelly, & Friedman, 1994;Dahlman, 2017;Lippke, 2015). Friedman (1999) argues that jurors should start a trial by regarding the defendant in the same way they would any random passer-by on the street.…”