The time course of processing external and internal features of unfamiliar faces

The time course of processing internal and external features was studied in a face-matching task in which participants had to match target and test faces, which differed in their external (hair and face outlines) or internal features (eyes, nose, mouth), or both. To this end, three different definitions of 'same' were used: same trials were defined as full congruency between target and test faces or as congruency in external or in internal features only. The results of three experiments provide an evidence for very fast matching of faces on the basis of external or internal features. Maximal performance is achieved already with 90 ms exposure time and longer exposure (120 ms, 150 ms, self-determined) time did not improve accuracy. The study suggests that unfamiliar faces can be matched more accurately on the basis of external vs internal features. There is no inversion effect for facial features, while matching of whole faces is impaired by orientation

Categorical perception effects for facial identity in robustly represented familiar and self-faces: The role of configural and featural information

Categorical perception of robustly represented faces (self, friend) and unfamiliar faces is investigated, and the relative roles of configural and featural information are examined. Participants performed identification and discrimination tasks on morph series containing the self-face and a friend's face (self–Friend 1), two friends' faces (Friend 2–Friend 3), and two unfamiliar faces (Unfamiliar 1–Unfamiliar 2), presented in upright and inverted orientations. For upright faces, categorical perception effects were observed for both familiar morph series but not for the unfamiliar morph series, suggesting that robust representation is a requirement for categorical perception in facial identity. For inverted faces, categorical perception was observed for the self–Friend 1 morph series only. This suggests that categorical perception is tied to configural processing for familiar non-self-faces, but can be observed for self-faces during featural processing—consistent with evidence that self-face representations contain strong configural and featural components. Finally, categorical perception is not enhanced by the presence of the self-face relative to other familiar faces when upright, but shows a trend of being enhanced for self-faces when inverted, adding to the debate on the ways in which robustly represented faces can elicit categorical perception