Face Distortion Aftereffects Evoked by Featureless First-Order Stimulus Configurations

Abstract

After prolonged exposure to a distorted face with expanded or contracted inner features, a subsequently presented normal face appears distorted toward the opposite direction. This phenomenon, termed as face distortion aftereffect (FDAE), is thought to occur as a result of changes in the mechanisms involved in higher order visual processing. However, the extent to which FDAE is mediated by face-specific configural processing is less known. In the present study, we investigated whether similar aftereffects can be induced by stimuli lacking all the typical characteristics of a human face except for its first-order configural properties. We found a significant FDAE after adaptation to a stimulus consisting of three white dots arranged in a triangular fashion and placed in a gray oval. FDAEs occurred also when the adapting and test stimuli differed in size or when the contrast polarity of the adaptor image was changed. However, the inversion of the adapting image as well as the reduction of its contrast abolished the aftereffect entirely. Taken together, our results suggest that higher-level visual areas, which are involved in the processing of facial configurations, mediate the FDAE. Further, while adaptation seems to be largely invariant to contrast polarity, it appears sensitive to orientation and to lower level manipulations that affect the saliency of the inner features.

Face perception inherits low-level binocular adaptation

“…For example, Afraz and Cavanagh (2009) argue that face aftereffects show transfer across retinal position, orientation, and size that far exceed the tuning widths of low-level mechanisms early in the processing stream; they argue that their results are consistent with the site of adaptation being the high-level mechanisms that process faces. Similar arguments have been made by many other researchers (e.g., Hills & Lewis, 2012;Hole, 2011;Leopold, O'Toole, Vetter, & Blanz, 2001;Vakli, Németh, Zimmer, Schweinberger, & Kovács, 2012;Watson & Clifford, 2003;Yamashita, Hardy, De Valois, & Webster, 2005;Zhao & Chubb, 2001). On the other hand, Dickinson and Badcock (2013) argue that the transfer across retinal position in these studies may have been mediated by inadvertent eye movements, while transfer across changes in size and orientation could still have been mediated by low-level processes.…”

The face evoked steady-state visual potentials are sensitive to the orientation, viewpoint, expression and configuration of the stimuli

“…In addition, the influence of second-order relations on face discrimination showed a positive correlation with individual face recognition skills (Rotshtein et al, 2007). High-level face aftereffects can be induced by schematic faces lacking all the typical facial features, indicating the role of higher level visual areas in the coding of face configuration (Vakli et al, 2012). Accordingly, functional imaging studies have shown that regions of the fusiform gyrus overlapping with (Goffaux et al, 2009;Rhodes et al, 2009;Rotshtein et al, 2007), or adjacent to face-preferring voxels are sensitive to the spacing of features.…”

Aftereffects in face processing

“…This indicates that the representation of unfamiliar faces is distinct to famous faces, but both share some similiarities with the representation of personally familiar and self faces. Finally, aftereffects in famous faces transfer across viewpoint and photographic negation but not across orientation (Hills and Lewis, 2012;Vakli et al, 2012) indicating the representation of familiar faces is more robust than unfamiliar faces.…”

“…In one of the most inovative studies in face aftereffects, Vakli et al (2012) have shown that the FDAE can be caused by gray stimuli with white dots in the triangular configuration of the internal facial features. This indicates that higher-level visual areas involved in the processing of facial configurations mediate the FDAE.…”