Data from: Perceptual expertise in forensic facial image comparison

Forensic facial identification examiners are required to match the identity of faces in images that vary substantially, owing to changes in viewing conditions and in a person's appearance. These identifications affect the course and outcome of criminal investigations and convictions. Despite calls for research on sources of human error in forensic examination, existing scientific knowledge of face matching accuracy is based, almost exclusively, on people without formal training. Here, we administered three challenging face matching tests to a group of forensic examiners with many years' experience of comparing face images for law enforcement and government agencies. Examiners outperformed untrained participants and computer algorithms, thereby providing the first evidence that these examiners are experts at this task. Notably, computationally fusing responses of multiple experts produced near-perfect performance. Results also revealed qualitative differences between expert and non-expert performance. First, examiners' superiority was greatest at longer exposure durations, suggestive of more entailed comparison in forensic examiners. Second, experts were less impaired by image inversion than non-expert students, contrasting with face memory studies that show larger face inversion effects in high performers. We conclude that expertise in matching identity across unfamiliar face images is supported by processes that differ qualitatively from those supporting memory for individual faces.法医面部识别鉴定人员（forensic facial identification examiners）需对因拍摄条件及个体外貌变化而存在显著差异的面部图像开展身份匹配工作，此类匹配结果将直接影响刑事侦查的进程与走向以及定罪裁决的最终结果。尽管学界已呼吁开展法医鉴定中人为误差来源的相关研究，但目前关于面部匹配（face matching）准确率的科学认知，几乎完全基于未接受过专业训练的人群的实验数据。本研究针对一群拥有多年为执法及政府机构开展面部图像比对工作经验的法医面部识别鉴定人员，施测了三项高难度的面部匹配测试。实验结果显示，该群体的表现优于未受训参与者与计算机算法（computer algorithms），这首次为这类人员是该任务领域的专家这一结论提供了实证依据。值得注意的是，通过计算融合多位专家的作答结果，可实现近乎完美的任务表现。研究结果同时揭示了专家与非专家在任务表现上的质性差异：其一，在更长的图像呈现时长下，法医面部识别鉴定人员的表现优势最为显著，这表明法医比对过程涉及更为深入的信息加工与比对环节；其二，与面部记忆研究中显示高表现者受面部倒置（image inversion）效应影响更大的结论相悖，法医专家受图像倒置的干扰程度低于非专家学生群体。综上，跨陌生面部图像进行身份匹配的专业能力，其背后的认知加工机制与支持个体面部记忆的机制存在质性差异。