Form identification in peripheral vision

Abstract

Outlined and solid-sur/aced metric histoforms and polygons we;e employed in an identification task where choice forms were fixed at 0 deg and target forms at six points along the temporal horizontal meridian in the periphery (nasal retina). Accuracy in the identification of solid-surfacedpolygons in the far periphery (80 deg from the fovea) was much higher than has been previously reported. Polygons were identified more quickly than h istaforms, but a significant difference was not obtained between the speed of identification of outlined and solid shapes. Combined speed and error data indicated that shape [histoform or polygon) is the most salient dimension ofa form less than 50 deg from the fovea. whereas beyond 50 deg from the fovea the surface (outlined or solid) of a form is its most salien t dimension. Finally. comparisons of the functional relations provided by these performance data with anatomical and physiological data produced the following hypothesis: Spatial summation ofrod receptors beyond 20 deg of angular eccentricity in the nasal retina is directly proportional to the density of rod receptors.

Preattentive and cognitive effects on perceptual completion at the blind spot

“…Recent evidence (Kawabata, 1982) suggests that fIlling in at the blind spot is contingent upon the visual systern's response to stimulation of an area of the retina directly around the optic disk, falling between 3 0 and 5.2 0 from the center of the blind spot; the functional size of the blind spot is 3 0 in diameter (Menzer & Thurmond, 1970). Filling in is also dependent upon similarity grouping, suggesting that the process of completion occurs with respect to the perceptual segregation of different stimuli (Kawabata, 1984).…”

The Influence of Eccentricity, Contrast, and Angular Extent on the Perception of Peripheral Apparent Motion

“…In terms of form perception, Zigler et al, (1930) found a significant drop in form identification between 25' and 30' . Menzer and Thurmond (1970) found that accuracy in the identification of solid-surfaced polygons in the far periphery (80' from the fovea) was much higher than had been previously reported, and hypothesized that spatial summation of rod receptors beyond 20' of angular eccentricity in the nasal retina was directly proportional to the density of rod receptors.…”

A minor perturbing effect of retinal locus on dot pattern recognition: Rejection of a possible artifact

“…1 the circled dots represent the ones that were omitted in the original experiment-the sides being omitted in certain trials and the corners in others.) Since it is known that, under certain conditions, retinal locus may play an important role in form r e c o g n i tion (Hershenson, 1969;Menzer & Thurmond, 1970), the possibility that retinal locus or some difference in acuity as a function of locus might have substantially biased our data must be considered.…”