Eyewitness Decision Processes: A Valid Reflector Variable

Abstract

Identification accuracy can be predicted from eyewitnesses’ self-reported decision processes but their ability to improve prediction beyond using confidence and response time alone has not been established. Typically, decision processes are measured via one or five self-report questions; we explored whether a more nuanced questionnaire could improve prediction. In 2015, participants from an Australian university viewed a mock-crime video (manipulated to create a strong or weak memory), viewed a target-present or -absent lineup, and completed 17 decision process items. An exploratory factor analysis on choosers’ (n = 391) responses revealed three correlated factors, broadly reflecting Automatic Responses, Relative Judgment, and Absolute Judgment. The three-factor solution had adequate fit for both memory strength conditions and good internal reliability y (McDonald’s ωs = .93, .89, and .74, respectively). Critically, scores produced from the questions loading on the Automatic Responses and Relative Judgment factors predicted unique variance in identification accuracy beyond what was accounted for by confidence and response time. Self-reported decision processes may be a practically useful reflector of identification accuracy.