Judging guilt and accuracy: highly confident eyewitnesses are discounted when they provide featural justifications

ABSTRACT

Jurors are heavily swayed by confident eyewitnesses. Are they also influenced by how eyewitnesses justify their level of confidence? Here we document a counter-intuitive effect: when eyewitnesses identified a suspect from a lineup with absolute certainty (‘I am completely confident’) and justified their confidence by referring to a visible feature of the accused (‘I remember his nose’), participants judged the suspect as less likely to be guilty than when eyewitnesses identified a suspect with absolute certainty but offered an unobservable justification (‘I would never forget him’) or no justification at all. Moreover, people perceive an eyewitness’s identification as nearly 25% less accurate when the eyewitness has provided a featural justification than an unobservable justification or simply no justification. Even when an eyewitness’s level of confidence is clear because s/he has expressed it numerically (e.g. ‘I am 100% certain’) participants perceive eyewitnesses as not credible (i.e. inaccurate) when the eyewitness has provided a featural justification. However, the effect of featural justifications – relative to a confidence statement only – is maximal when there is an accompanying lineup of faces, moderate when there is a single face and minimal when there is no face at all. The results support our Perceived-Diagnosticity account.

KEYWORDS:

• Eyewitness identification
• confidence
• juror decision-making
• eyewitness testimony
• credibility

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Science Foundation under Grant No. 1632174.