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需要对因拍摄条件变化以及个体外貌改变而存在显著差异的面部图像进行身份匹配。此类身份匹配结果会直接影响刑事调查的进程、案件走向以及定罪判决。尽管学界呼吁开展法医鉴定中人为误差来源的相关研究，但当前关于面部匹配准确率的科学认知，几乎完全基于未接受过专业训练的普通人群的实验数据。本研究针对一群拥有多年执法与政府机构面部图像比对经验的法医鉴定人员，实施了三项高难度面部匹配测试任务。实验结果显示，法医鉴定人员的表现优于未受训参与者与计算机算法，这首次为“此类鉴定人员是该任务的专家”提供了实证依据。值得注意的是，通过计算方式融合多位专家的匹配结果，可实现近乎完美的任务表现。研究结果还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，鉴定人员的性能优势最为显著，这表明法医鉴定人员会开展更充分的图像比对流程；其二，与面部记忆研究中“高表现者受面部倒置效应影响更大”的结论相反，专家受图像倒置的干扰程度低于未受训的学生群体。综上，跨陌生面部图像进行身份匹配的专业能力，其背后的认知机制与支撑个体面部记忆的机制存在质性差异。