Figure 1.

In each experiment, human subjects performed a visual categorization task (A) and a visual search task (B) on the same objects. In the visual categorization task, subjects saw a briefly presented image followed by a noise mask and had to indicate whether or not the object belonged to a particular category (in this example, animal). In the visual search task, subjects saw an array containing an oddball and had to indicate whether the oddball appeared on the left or right half of a vertical red line on the screen. No instructions were given as to the nature or category of the oddball target.