Abstract
Background: While expression creates short-term dynamic changes in faces, age imparts a long-term dynamic change. In contrast to the work on expression, how facial age is represented in the human visual system has seldom been investigated with adaptation methods. Objective: As a parallel to our prior work on expression aftereffects, we studied the ability of age adaptation to transfer across face identity, face and non-face visual stimuli and sensory modality. Methods: We investigated facial age aftereffects using a perceptual bias paradigm in 48 healthy subjects. In a first experiment we examined whether face age aftereffects could be generated and how these were affected by changes in identity between adapting and test stimuli. In a second experiment, we asked whether hands, body silhouettes or body images at different extremes of age generated facial age aftereffects. In a final experiment, we asked whether young and old voices could do the same. Results: Age aftereffects were reduced but still significant when the identity of the face was changed between the adapting and test stimuli. Although body silhouettes and grayscale body images failed to generate age aftereffects in faces, we did find modest cross-stimulus transfer of age adaptation from hands to faces. There was no cross-modal transfer of aftereffects from voices to faces. Conclusions: The effects of identity on age aftereffects parallel our findings for the effects of identity on expression aftereffects, suggesting both identity-specific and identity-invariant components of age aftereffects. Transfer between hands and faces may reflect either the contribution of common properties like skin texture that may be potent age cues, or a convergence of representations at a visual semantic level.
NSERC Discovery Grant RGPIN 355879-08.