Adults' Awareness of Faces Follows Newborns' Looking Preferences

From the first days of life, humans preferentially orient towards upright faces, likely reflecting innate subcortical mechanisms. Here, we show that binocular rivalry can reveal face detection mechanisms in adults that are surprisingly similar to inborn face detection mechanism. We used continuous flash suppression (CFS), a variant of binocular rivalry, to render stimuli invisible at the beginning of each trial and measured the time upright and inverted stimuli needed to overcome such interocular suppression. Critically, specific stimulus properties previously shown to modulate looking preferences in neonates similarly modulated adults' awareness of faces presented during CFS. First, the advantage of upright faces in overcoming CFS was strongly modulated by contrast polarity and direction of illumination. Second, schematic patterns consisting of three dark blobs were suppressed for shorter durations when the arrangement of these blobs respected the face-like configuration of the eyes and the mouth, and this effect was modulated by contrast polarity. No such effects were obtained in a binocular control experiment not involving CFS, suggesting a crucial role for face-sensitive mechanisms operating outside of conscious awareness. These findings indicate that visual awareness of faces in adults is governed by perceptual mechanisms that are sensitive to similar stimulus properties as those modulating newborns' face preferences.

自生命诞生之初，人类便会优先将注意力转向正置面孔，这一现象大概率反映了先天存在的皮层下机制。本研究表明，双眼竞争（binocular rivalry）可用于揭示成人的面孔检测机制，该机制与先天面孔检测机制惊人地相似。我们采用了连续闪烁抑制（continuous flash suppression, CFS）——一种双眼竞争的变体范式——在每个试次开始时使刺激物无法被感知，并测量了正置与倒置刺激克服这种间眼抑制所需的时长。至关重要的是，此前被证实可调节新生儿视觉偏好的特定刺激特征，同样能调节成人在连续闪烁抑制范式下对呈现面孔的感知觉知。其一，正置面孔在克服连续闪烁抑制上的优势，会受到对比度极性（contrast polarity）与光照方向的显著调节。其二，当由三个暗斑点组成的示意图模式符合眼睛与嘴巴的类面孔构型时，这类刺激的抑制时长会更短，且该效应同样受对比度极性的调节。在未采用连续闪烁抑制的双眼对照实验中，并未观测到此类效应，这表明在有意识觉知之外运作的面孔敏感机制发挥了关键作用。本研究结果表明，成人对面孔的视觉觉知，由对相似刺激特征敏感的感知机制所调控——这类特征同样会调节新生儿的面孔偏好。