Low prevalence match and mismatch detection in simultaneous face matching: Influence of face recognition ability and feature focus guidance

Abstract

Accurate simultaneous face matching of photos of unfamiliar faces to verify identity is key to many security and policing operations. However, matching is error-prone, especially when the prevalence of target items is low. In two experiments, the current research examined whether the use of internal or external facial feature guidance scales, and recruitment of participants with superior face recognition ability would reduce low prevalence effect impact. In Experiment 1, no information as to low prevalence of items was provided. Super-recognisers (n = 317) significantly outperformed typical-range-ability controls (n = 452), while internal feature guidance significantly enhanced accuracy in all prevalence conditions (10-90%, 50-50%, 90-10% mismatched-matched). However, an unexpected paradoxical prevalence criterion shift effect in controls meant accuracy tended to be highest in low prevalence conditions. In Experiment 2, top-end-of-typical range ability participants (n = 567) were informed as to low matched or mismatched item prevalence, and this time, the expected low prevalence effects were observed. No facial feature focus guidance effects were significant. The results enhance theoretical understanding of low prevalence effects while offering support for the deployment of super-recognisers, and the use of facial feature guidance scales in the identity verification workplace.