Department of Psychology, University of Edinburgh, Edinburgh, UK.
Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
Sci Rep. 2022 May 10;12(1):7640. doi: 10.1038/s41598-022-11717-4.
Faces convey information essential for social interaction. Their importance has prompted suggestions that some facial features may be processed unconsciously. Although some studies have provided empirical support for this idea, it remains unclear whether these findings were due to perceptual processing or to post-perceptual decisional factors. Evidence for unconscious processing of facial features has predominantly come from the Breaking Continuous Flash Suppression (b-CFS) paradigm, which measures the time it takes different stimuli to overcome interocular suppression. For example, previous studies have found that upright faces are reported faster than inverted faces, and direct-gaze faces are reported faster than averted-gaze faces. However, this procedure suffers from important problems: observers can decide how much information they receive before committing to a report, so their detection responses may be influenced by differences in decision criteria and by stimulus identification. Here, we developed a new procedure that uses predefined exposure durations, enabling independent measurement of perceptual sensitivity and decision criteria. We found higher detection sensitivity to both upright and direct-gaze (compared to inverted and averted-gaze) faces, with no effects on decisional factors. For identification, we found both greater sensitivity and more liberal criteria for upright faces. Our findings demonstrate that face orientation and gaze direction influence perceptual sensitivity, indicating that these facial features may be processed unconsciously.
面部传达了对社会互动至关重要的信息。其重要性促使人们提出了一些观点，即某些面部特征可能是无意识加工的。尽管一些研究为这一观点提供了经验支持，但这些发现究竟是由于感知加工还是知觉后决策因素仍不清楚。面部特征无意识加工的证据主要来自于打破连续闪光抑制（b-CFS）范式，该范式测量了不同刺激克服眼间抑制所需的时间。例如，先前的研究发现，直立的面部比倒置的面部报告得更快，直视的面部比斜视的面部报告得更快。然而，该程序存在重要问题：观察者可以在做出报告之前决定他们接收多少信息，因此他们的检测反应可能受到决策标准差异和刺激识别的影响。在这里，我们开发了一种新的程序，该程序使用预定义的曝光持续时间，能够独立测量感知敏感性和决策标准。我们发现，对直立和直视（与倒置和斜视相比）的面部有更高的检测敏感性，而对决策因素没有影响。对于识别，我们发现直立的面部有更高的敏感性和更宽松的标准。我们的研究结果表明，面部方向和注视方向会影响感知敏感性，这表明这些面部特征可能是无意识加工的。
