Figure 3.

A, Neuronal recording experiments involved rapid serial presentation of randomly interleaved images centered 2° contralateral to fixation. Responses to the six image sets shown in Figure 1 were collected in separate blocks of trials. B, On each trial of a visual search session, a hexagonal array of images at 5° eccentricity was presented. One of the images was an oddball. The oddball and the distractors belonged to one of the pairs shown in Figure 2. The observer was required to press the right or left key according to whether the oddball was on the right or left. The difference in eccentricity between images in the neuronal and visual search experiments arose from the need to optimize the placement of the images in the neuron's receptive field during recording and to optimize the spacing of the items in the array during visual search.