Abstract
Humans perceive faces holistically rather than as a set of separate features (Sergent, 1984). Previous work demonstrates that some individuals are better at this holistic type of processing than others (Wang et al., 2012). Here, we show that there are unique individual differences in holistic processing of specific faces. To examine individual differences in holistic processing, we used Mooney faces (stimuli extracted from Schwiedrzik, Melloni, & Schurger, 2018), which are readily perceived as faces despite lacking low-level segmentable face-specific features. We used the magnitude of the face inversion effect as a measure of the degree to which individual Mooney faces were processed holistically. In each experimental trial, participants viewed two images for two seconds: an intact Mooney face and a scrambled version of the same face. The intact face was presented upright or inverted randomly on each trial. After the display disappeared, participants were asked to determine which of the two images was a face (regardless of the orientation). We calculated a holistic processing index for each Mooney face in our stimulus set by comparing the difference in accuracy between upright-face trials and inverted-face trials. The images varied considerably in this inversion effect, but there was little between-subject agreement; specific faces that were processed holistically by one observer were not by other observers. Individual subject data, on the other hand, was highly reliable and consistent. Our findings reveal that there are idiosyncratic individual differences in the perception of Mooney faces.