Visual marking: evidence for inhibition using a probe-dot detection paradigm.

Watson and Humphreys (1997, 1998) have recently demonstrated that new objects can be prioritized for visual attentional processing by the top-down attentional inhibition of old objects already in the field, a mechanism they called visual marking. The experiments reported here show that the detection of a dim probe dot is impaired when it falls at the location of an old object (Experiments 1 and 3) but that this occurs only in conditions in which it is advantageous for subjects to mark (inhibit) old objects (Experiment 2). These results further support previous work showing that visual marking is based on the inhibition of the locations of old objects and that visual marking can be flexibly applied (or withheld), depending on the goals of current behavior.