Abstract
Facial expressions are used as critical social cues in everyday life. Adaptation to expressions causes expression aftereffects. These aftereffects are thought to be representative of face-specific neural mechanisms and processes, and are used by researchers as evidence to investigate the nature of these mechanisms. However, recent evidence suggests expression aftereffects could be at least partially explained by the inheritance of lower-level tilt adaptation through the visual hierarchy. We investigated whether expression aftereffects contain a significant contribution of tilt adaptation. Participants completed an expression adaptation task in which we controlled for the influence of tilt by rotating the position of the adaptor relative to the test stimuli. Although tilt adaptation was found to make a significant contribution to the expression aftereffect, expression aftereffects still remained after controlling for tilt, indicating that expression aftereffects contain contributions from multiple levels of the visual hierarchy, including both low-level tilt adaptation and higher-level, face-specific adaptation.