Abstract
Adaptation to distorted faces can shift what individuals identify to be a prototypical or attractive face. This effect occurs both across and within sub-categories of human faces, such as gender and race/ethnicity, suggesting that there is a common coding mechanism for human faces (a single face space) and dissociable coding mechanisms for subgroups of human faces. But does this face space extend to non-human faces? The construct of the “uncanny valley” suggests that as human-like features increase, people respond more positively, but at a distinct point, there is an “uncanny valley,” a region where the deviations from humanness are stronger than the reminders of humanness, which creates feelings of uncanniness and repulsion. This points to a significant divide between human faces and other faces such that they may not share a common face space. It is also important to note that low-level shape adaptation can affect high-level face processing but is position dependent and hence not face-specific. Thus, it is unclear whether there is a common coding mechanism for all faces, including non-human faces, that is nevertheless specific to faces. This study assessed whether there is a single face space common to both human and cartoon faces by testing whether adaptation to cartoon faces can affect perception of human faces. Participants were shown Japanese animation cartoon videos containing faces with abnormally large eyes. Using animated videos eliminated the possibility of position dependent adaptation (because the faces appear at many different locations) and more closely simulated naturalistic exposure. Adaptation to cartoon faces with large eyes significantly shifted preferences for human faces toward larger eyes, consistent with a position independent, common representation for both cartoon and human faces. This supports the possibility that there are representations that are specific to faces yet common to all kinds of faces.