Perception of spatial order in extrafoveal vision

Perception of spatial order in central and extrafoveal vision was investigated by means of a task in which observers judged the relative position of a target line segment in a briefly flashed array of six line segments. The line arrays were size-scaled in extrafoveal vision according to the cortical magnification factor derived from the cone and ganglion cell distributions across the human retina, i.e. the stimulus representations in the striate cortex were of equal size in central and eccentric vision. In central vision, observers could judge the relative position of the target with high accuracy but in extrafoveal vision the task was more difficult, especially with short interline distances. However, performance was well above chance level also in extrafoveal vision.