Figure 1.

Experimental tasks. A, Orientation weight estimation task (Session 1): observers performed a fixation task and detected the appearance of the green color (left), peripheral gratings were displayed in four of the eight possible positions (right). B, Reward learning task (Session 2): observers performed a visual search task and reported the dot color inside a tilted Gabor. The Gabor inside the white circle is the target. C, Categorical visual search task (Session 3): observers searched for a categorically defined Gabor (i.e., steep or shallow orientation) and reported the dot color inside the target. The Gabor inside the black circle is the target, and the Gabor inside the white circle is the distractor (the same orientation with the target in the reward learning task). The dashed circles were not visible in the experiment.