Component processes of human face perception in typical and atypical individuals

人脸感知是人类社会交往的重要组成部分。它引导我们如何与他人互动，使我们能够识别个人，确定他们的情绪状态，并判断他们的吸引力和可信度。由于面部感知的运作如此轻松可靠，我们很少再考虑它。但事实上，人脸的感知和识别是一项困难的成就，它是基于复杂且知之甚少的机制。只有当遇到没有任何一般知觉或智力障碍，没有任何神经损伤史的人时，面部处理的真实的困难才会变得明显，这些人发现很难从他们的脸上认出家人和朋友。我们和其他研究小组对人脸处理的各个方面进行的行为测试表明，许多患有发展性面孔失认症（DP）的人在物体识别方面没有类似的问题，这表明人脸和非人脸物体是通过不同的机制处理的。所有DP在身份处理方面表现出严重的缺陷，但面部处理的其他方面，如面部部位和面部结构的感知或面部表情的情感处理，可以是完整的或受损的，这表明DP是一种异质性条件。在我们目前ESRC资助的研究项目中，我们使用行为和电生理措施（事件相关脑电位，ERP）的组合，以获得新的见解，面部处理的哪些方面在DP中受损。到目前为止，我们的研究结果指出，面部处理的早期视觉感知阶段是影响DP患者面部识别问题的主要原因。例如，具有完整面部感知的人处理直立面部和倒置面部的方式非常不同，这被解释为直立面部的感知是“立体”或“整体”的证据，而倒置面部的处理方式则是以质的不同的“基于部分”的方式。我们发现，DP患者在直立和倒置面部之间没有表现出这些典型的处理差异，这表明他们以一种独特/整体的方式处理直立面部的能力没有得到适当的发展。为了更精确地找出DP和具有完整面部处理的人之间的面部感知如何不同，我们将使用专门设计用于参与面部处理的不同方面的面部和非面部刺激进行一系列实验（例如，对诸如眼睛的突出面部部分的感知、面部构造的处理、从不同视角感知面部、使用面部感知来记住个体面部），以找出在患有DP的人中哪些过程正常运行以及哪些过程受损。我们还将研究是否DPs和非受损的人看脸的不同，以及他们是否使用不同的部分时，试图识别它。找出哪些方面的面孔知觉工作良好，哪些是受损的DPs将有重要的意义，我们了解的机制，面孔知觉的完整的面孔处理能力的人。这也将大大扩展我们对为什么有些人在面部识别方面有严重缺陷的认识。这种缺陷可能对他们的社会生活产生巨大影响。许多人由于感觉到冷落而难以维持友谊，他们在工作中的识别困难可能非常令人不安。

Face perception is an essential component of human social interaction. It guides how we interact with others by enabling us to recognize individuals, identify their emotional state, and judge their attractiveness and trustworthiness. Because face perception operates so effortlessly and reliably, we rarely give it a second thought. But in fact, face perception and recognition are difficult achievements that are based on complex and poorly understood mechanisms. The real difficulty of face processing only becomes apparent when meeting people without any general perceptual or intellectual impairment, and without any history of neurological damage, who find it extremely hard to recognize family and friends from their faces. Behavioural tests of various aspects of face processing conducted by us and by other groups have shown that many of these people with developmental prosopagnosia (DP) have no comparable problems with object recognition, which indicates that faces and non-face objects are processed by different mechanisms. All DPs show severe deficits in the processing of identity, but other aspects of face processing, such as the perception of face parts and face configurations or the processing of emotional facial expression, can be intact or impaired, suggesting that DP is a heterogeneous condition. In our current ESRC-funded research project, we use a combination of behavioural and electrophysiological measures (event-related brain potentials, ERPs) to gain new insights into which aspects of face processing are damaged in DP. Our results so far point to early visual-perceptual stages of face processing as a major cause of the face recognition problems that affect individuals with DP. For example, people with intact face perception process upright faces and inverted faces very differently, which is interpreted as evidence that the perception of upright faces is "configural" or "holistic", whereas inverted faces are processed in a qualitatively different "part-based" fashion. We have found that people with DP do not show these typical processing differences between upright and inverted faces, indicating that their ability to process upright faces in a configural/holistic fashion did not develop properly. To find out more precisely how face perception differs between DPs and people with intact face processing, we will conduct a series of experiments with face and non-face stimuli that are specifically designed to engage different aspects of face processing (e.g., the perception of salient face parts such as the eyes, the processing of facial configurations, perceiving faces from different viewpoints, using face perception to remember individual faces), to find out which processes operate normally and which are impaired in people with DP. We will also study whether DPs and non-impaired people look at faces differently, and whether they use different parts of a face when trying to identify it. Finding out which aspects of face perception work well and which are impaired in DPs will have important implications for our understanding the mechanisms that underlie face perception in people with intact face processing abilities. It will also greatly expand our knowledge of why some people have severe deficits in face recognition. Such deficits can have an enormous impact on their social lives. Many have difficulty maintaining friendships due to perceived snubs and their recognition difficulties at work can be extremely troubling.