Figure 7.

Ideal observers for overt and covert attention. a. Schematic of three types of stimuli in a single fixation search task. The subjects’ task was to indicate (following a brief presentation followed by a mask) whether or not the display contained the target object at one the cued locations (rectangular boxes). b. Accuracy in the single fixation search task as a function of the number of cued locations where the target might appear, for a subject and two model searchers. Solid curves show ideal observer predictions. c. Stimuli for multiple fixation search task. A small Gabor target was randomly located in background texture of noise having the average power spectrum of natural images. Search began at the center of the display; the white dots and lines show a hypothetical fixation sequence. d. These temperature plots show the distribution of fixation locations in the display combined over all trials (excluding the first fixation which was always at the center of the display), for the human and two model searchers.