Figure 1.

Experimental protocol and behavioral results. A, Illustration of the timing and sequence of events within an example trial. Each trial consisted of a fixation period followed by a memory cue, then by a cue-to-probe interval, and finally by either a visual search display (on standard search trials), a memory probe (on memory catch trials), or no display (on cue-only trials). Trials were separated by a jittered intertrial interval (data not shown, see Materials and Methods, Experimental protocol). In the example trial displayed here, the WM cue would be considered an invalid cue for the visual search, because the WM cue surrounds a search distracter (the search target is the tilted bar). B, Median search response time is plotted as a function of WM cue validity and whether the cue validity was predictable.