Figure 1.

The tasks. a, The memory-guided saccade task. After the monkey fixated on a central spot, a peripheral stimulus identical to the fixation spot was flashed for 50 ms at one of six or eight locations. After a delay, the fixation spot was removed, and the monkey was instructed to make a saccade to the remembered target location. b, The manual lever search task. After the monkey grasped a lever in the vertical position, a small fixation cross appeared. After the monkey fixated on the central cross, a search array appeared in which one of the stimuli was different. In the location search (“Location”), the monkey was rewarded for turning the lever in the same direction as a different-colored stimulus in relation to the fixation cross. In the identity search (“Identity”), the monkey was rewarded for turning the lever in the same direction as the gap in the C stimulus.