Verbal and Numeric Eyewitness Confidence Differentially Affect Decision-Making

Abstract

Eyewitness confidence is typically communicated verbally (e.g., certain). Interpretations for verbal confidence statements are variable which could affect decision-making. I explored the extent to which confidence format (i.e., verbal vs. numeric) influences juror decision-making. Participants (N = 468) read a trial vignette in which an expert witness draws attention to the eyewitness's confidence in their suspect identification (uncertain, or certain, or 28%, or 88%). Participants rated the expert's recommendation, rendered a conviction decision, and provided confidence in their decision on a scale of 0 = Not at all confident to 10 = Completely confident. Mock-jurors were more likely to convict when confidence was high. However, mock-jurors were also more likely to convict when confidence was presented verbally. This effect may be attributable to the ambiguity verbal confidence affords, allowing for interpretation in congruence with the eyewitness's identification decision.