Figure 1
Schematic illustration of stimuli.
Stimuli were always white and presented on a black background, but are shown here and represented in subsequent figures in red (5 deg), green (10 deg) and blue (15 deg). Unscaled stimuli (top row) were the same retinal size at each eccentricity; scaled stimuli (middle row) were larger at more eccentric locations; crowded stimuli (bottom row) were the same size at each eccentricity. As crowding increases with retinal eccentricity, different spatial distances were required between target and flanker to equate performance. Subjects were trained with stimuli presented at 5 and 15 degrees. Vernier alignment threshold at 10 degrees was only measured on the first and last training sessions.
