Humans show improved recognition for faces from their own social group relative to faces from another social group. Yet before faces can be recognized, they must first be detected in the visual field. Here, we tested whether humans also show an ingroup bias at the earliest stage of face processing – the point at which the presence of a face is first detected. To this end, we measured viewers' ability to detect ingroup (Black and White) and outgroup faces (Asian, Black, and White) in everyday scenes. Ingroup faces were detected with greater speed and accuracy relative to outgroup faces (Experiment 1). Removing face hue impaired detection generally, but the ingroup detection advantage was undiminished (Experiment 2). This same pattern was replicated by a detection algorithm using face templates derived from human data (Experiment 3). These findings demonstrate that the established ingroup bias in face processing can extend to the early process of detection. This effect is ‘colour blind’, in the sense that group membership effects are independent of general effects of image hue. Moreover, it can be captured by tuning visual templates to reflect the statistics of observers' social experience. We conclude that group bias in face detection is both a visual and a social phenomenon.

中文翻译：

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人脸检测的内群外差异

相对于另一个社会群体的面孔，人类对自己社会群体的面孔表现出更高的识别度。然而，在识别人脸之前，必须首先检测到人脸在视野中。在这里，我们测试了人类在面部处理的最早阶段是否也表现出内群体偏见——即首次检测到面部存在的时间点。为此，我们测量了观众在日常场景中检测内群体（黑人和白人）和外群体面孔（亚洲人、黑人和白人）的能力。相对于外群人脸，内群人脸的检测速度和准确度更高（实验 1）。去除面部色调通常会损害检测，但组内检测优势并未减弱（实验 2）。使用从人类数据派生的面部模板的检测算法复制了相同的模式（实验 3）。这些发现表明，面部处理中既定的群体内偏见可以扩展到早期检测过程。这种效果是“色盲”，从某种意义上说，群体成员效应独立于图像色调的一般效应。此外，它可以通过调整视觉模板来捕捉，以反映观察者社交体验的统计数据。我们得出结论，人脸检测中的群体偏见既是视觉上的和一种社会现象。