Picture-plane inversion leads to qualitative changes of face perception

Repetition probability effects for inverted faces

“…FIE is an observation that a 180-degree in-plane rotation impairs recognition significantly more for faces than for non-face objects. Most current studies suggest that since inversion preserves the low-level features of faces, the FIE is attributed to the interruption of higher-level processes such as the configural processing of spatial relationships of object parts as well as the face specific holistic processing (Rossion and Gauthier, 2002;Rossion, 2008; but see Yovel and Kanwisher, 2004 for another conclusion). Therefore, it seems that inversion leads to qualitatively different processing of stimuli belonging to categories of high expertise, such as faces.…”

“…Instead, information across the spatial relations of facial features are integrated into a holistic unit, gestalt or global representation that is more than the combined sum of individual features (Maurer et al, 2002). These configural and/or holistic processes 1 are specific, higher-level mechanisms of the encoding of upright faces and other categories of high expertise (Gauthier and Tarr, 2002;Rossion, 2008).…”

The evolution of face processing in primates

“…The configural information present in faces is integrated into a single perceptual whole through a fast-acting and relatively automatic process referred to as holistic processing [3,[57][58][59]. Tasks used to demonstrate holistic processing typically show that it is harder to identify individual facial features, such as the eyes, when they are embedded in a whole face than when presented in isolation (parts-to-wholes task, [59]), in an inverted face (inversion effect, [60]), or if presented within the context of an unnaturalistic face shape (composite task, [61]).…”

“…This is achieved using a holistic processing strategy where it is not just the presence of specific features, such as the eyes, nose and mouth, but the relative spatial arrangement of these facial features that becomes integrated into a single perceptual whole [1,2]. Moreover, these processes are orientation-dependent such that inverting faces interferes with the ability to process faces holistically, leading to impairments in the ability to detect subtle changes in the spacing of features [3]. Although they will not be covered in this review, neural specializations for face processing are also present in humans and consist of a network of distributed regions that show face-selective activity.…”

The ‘Double Face' Illusion

“…The causes of the effect of inversion are debated (Rossion 2008;Rossion 2009;Riesenhuber and Wolff 2009;Yovel 2009) but it seems agreed that our ability to process a face holistically is at least much reduced by inversion (e.g. Hole 1994).…”