Face adaptation: Investigating non-configural contrast alterations

The process of adapting facial representations plays a critical role in face perception and memory, representing an interplay of bottom-up and top-down mechanisms. This process allows individuals to recognize faces despite dynamic changes, for example, aging. However, a full understanding of the adaptation characteristics of non-configural facial information is still lacking in the face-processing literature. The present study investigates face aftereffects in response to facial contrast information, extending the research beyond recent studies on adaptation regarding brightness and color saturation information to a new non-configural facial information type. The research involved four experiments using celebrity face images manipulated for facial contrast, with intervals ranging from 300 ms (Experiment 1) to 5 min (Experiment 2) between adaptation and test phases. Experiment 3 used inverted adaptation faces to investigate whether adaptation effects transfer to upright test faces. The results demonstrate adaptation effects for facial contrast that are robust over time and do not transfer from inverted to upright faces. In addition, these effect sizes were compared to those of brightness and saturation information (Experiment 4), revealing no significant differences in magnitude. In general, the present findings suggest that non-configural facial contrast information is an integral part of face representations, representing an interplay of bottom-up and top-down mechanisms in face processing. All data are available on the Open Science Framework.