Blank Idan, Yovel Galit
Department of Psychology, Tel Aviv University, Israel.
J Vis. 2011 Jul 27;11(8):1-13. doi: 10.1167/11.8.15.
According to the face-space framework, faces are represented as locations in a multidimensional space, where the distance separating representations is proportional to the degree of dissimilarity between faces. The present study tested whether similarities between faces, and thus the structure of face-space, were tolerant to ("invariant" under) identity-preserving transformations such as changes in lighting or view. To examine the correspondence between the configurations of face-space under different transformations, perceived similarity was rated for two variants of a set of faces, differing either in illumination (Experiment 1) or viewpoint (Experiment 2). We found that similarity ratings within the first variant were highly correlated with ratings within the second variant. In addition, based on these ratings, a separate face-space was constructed for each variant using multidimensional scaling. Procrustean analysis revealed that the different spaces shared comparable structures. This correspondence serves as a face-space manifestation of the tolerance of identity representations. Accordingly, we suggest that tolerance may rely on the fact that similarities between faces under one transformation are isomorphic to similarity patterns under a different transformation. Thus, recognizing faces under varying viewing conditions may only require similarity evaluations within--rather than across--different transformations.
根据面部空间框架，面部被表示为多维空间中的位置，其中表示之间的距离与面部之间的不相似程度成正比。本研究测试了面部之间的相似性，以及由此产生的面部空间结构，是否能耐受（在身份保持变换下“不变”）诸如光照或视角变化等变换。为了检验不同变换下面部空间配置之间的对应关系，对一组面部的两个变体的感知相似性进行了评分，这两个变体在光照（实验1）或视角（实验2）上有所不同。我们发现第一个变体中的相似性评分与第二个变体中的评分高度相关。此外，基于这些评分，使用多维缩放为每个变体构建了一个单独的面部空间。普罗克汝斯忒斯分析表明，不同的空间具有可比的结构。这种对应关系是身份表示耐受性的面部空间表现。因此，我们认为耐受性可能依赖于这样一个事实，即一种变换下面部之间的相似性与另一种变换下的相似性模式同构。因此，在不同观看条件下识别面部可能只需要在不同变换内进行相似性评估，而不是跨变换评估。
