In line with this interpretation, the present findings suggest that only eye-specific low-level components of face shape adaptation resist interocular suppression. By contrast, binocular higher level components of face shape adaptation involving neurons beyond primary visual cortex appear to be entirely eliminated during suppression. Thus, visual awareness is necessary not only for adaptation to face identity, gender, race, and expression (Amihai et al.,
2011; Moradi et al.,
2005; Yang et al.,
2010) but also for adaptation to basic face shape. The elimination of face shape adaptation by interocular suppression is consistent with a multilevel view of binocular rivalry in which suppression occurs at multiple levels of the visual system (Sterzer, Kleinschmidt et al.,
2009; Tong et al.,
2006) but deepens as one moves up the visual hierarchy (Nguyen et al.,
2003), until near complete suppression in object-responsive areas of the ventral visual pathway (Fang & He,
2005; Moradi et al.,
2005; Pasley et al.,
2004; Sheinberg & Logothetis,
1997; Tong et al.,
1998). This view leaves open the possibility that recently discovered neural markers of residual processing in ventral areas during interocular suppression might carry behaviorally effective information about other stimulus properties, such as category membership (Sterzer et al.,
2008; Sterzer, Jalkanen et al.,
2009), familiarity (Jiang et al.,
2007), arousal and valence (Jiang, Costello, Fang, Huang, & He,
2006; Jiang & He,
2006; Jiang et al.,
2009; Sterzer, Hilgenfeldt, Freudenberg, Bermpohl, & Adli,
2011; Yang, Zald, & Blake,
2007), or social relevance (Stein et al.,
2011). Further studies are needed to elucidate the functional significance of such residual neural responses.