The studies mentioned above have demonstrated that natural scene categorization at the superordinate level (e.g., animal/non-animal or vehicle/non-vehicle) is feasible in the near absence of focal attention. However, it is generally recognized that object categorization—grouping different objects into one category and discriminating them from items from another category—can occur at different levels of specificity or detail (Rosch, Mervis, Gray, Johnson, & Boyes-Braem,
1976). Rosch et al. proposed a distinction between three category levels: superordinate level (e.g., discriminating an animal from a vehicle), basic level (e.g., discriminating a dog from another animal), and subordinate level (e.g., discriminating between a Dalmatian and another dog). Although the prevalent consensus supports the idea of a basic-level advantage (Murphy & Brownell,
1985), recent studies have suggested that access to basic visual categories takes longer processing time compared to superordinate visual categories and that this might occur at different stages of processing. First, more incoming information is required for basic than for superordinate level categorization. Indeed, global properties of an image are available with less presentation time than basic-level details (Fei-Fei, Iyer, Koch, & Perona,
2007; Greene & Oliva,
2009). Second, access to the basic-level category requires additional processing time. Reaction times are longer for basic than for superordinate-level categorization both for objects (Mace, Joubert, Nespoulous, & Fabre-Thorpe,
2009) and scenes (Joubert, Rousselet, Fize, & Fabre-Thorpe,
2007). These behavioral measures are consistent with electrophysiological studies reporting that global information is transmitted earlier than finer grained information (Sugase, Yamane, Ueno, & Kawano,
1999). The delay in accessing more detailed information at the basic level could reflect additional processing of stimulus information, perhaps as a result of feedback signals and/or attentional processing (Ahissar, Nahum, Nelken, & Hochstein,
2009; Cromer, Roy, & Miller,
2010; Freedman & Miller,
2008; Freedman, Riesenhuber, Poggio, & Miller,
2003; Meyers, Freedman, Kreiman, Miller, & Poggio,
2008).