An Object Substitution Theory of Visual Masking

The brief presentation of a visual display, although clearly visible when shown by itself, can be rendered invisible by the subsequent presentation of a second visual display in the same location. Recent studies of backward masking of this kind have revealed several new effects that are not predicted by standard theories of masking. Among these are masking by four small dots that surround but that do not touch the target object, and masking by a surrounding object that remains on display after the target has been turned off. A critical ingredient in both these masking effects is the focus of spatial attention: almost no masking occurs if attention can be rapidly focused on the target, but powerful masking ensues if attention to the target is delayed. A new theoretical framework, inspired by recent developments in neuroscience, is described to explain both these and more traditional forms of masking. In addition to accounting for backward masking, this framework sheds light on several other active areas of vision research, including work on the attentional blink, inattentional blindness, and change blindness. 122 From Fragments to Objects