Implicit perception and level of processing in object-substitution masking

Object-substitution masking (OSM) refers to reduced target discrimination when the target is surrounded by a sparse mask that does not overlap with the target in space but trails it in time. In four experiments, we used a novel paradigm to investigate the extent of processing of a masked target in OSM. We measured response-compatibility effects between target and mask, both when the offsets were simultaneous and when the offset of the mask was delayed. Evidence for both OSM and a dissociation between perception and awareness was found when detecting the match between the target and the mask required feature but not categorical analyses. Our results suggest that the locus of disruption in OSM is likely to be beyond feature analysis of the unreported target.