A brief display that is dearly visible when shown alone can be rendered inv
isible by the subsequent: presentation of a second visual stimulus. Several
recently described backward masking effects are not predicted by current t
heories of visual masking, including masking by four small dots that surrou
nd (but do not touch) a target object and masking by a surrounding object t
hat remains on display after the target object has been turned off. A cruci
al factor in both of these effects is attention: almost no masking occurs i
f attention can be rapidly focused on the target whereas powerful masking e
nsues if attention directed at the target is delayed. A new theory of visua
l masking inspired by developments in neuroscience, can account for these e
ffects, as well as more traditional masking effects. In addition, the new t
heory sheds light on related research, such as the attentional blink, inatt
entional blindness and change blindness.