Perceptual grouping across eccentricity

Abstract

Across the visual field, progressive differences exist in neural processing as well as perceptual abilities. Expansion of stimulus scale across eccentricity compensates for some basic visual capacities, but not for high-order functions. It was hypothesized that as with many higher-order functions, perceptual grouping ability should decline across eccentricity. To test this prediction, psychophysical measurements of grouping were made across eccentricity. Participants indicated the dominant grouping of dot grids in which grouping was based upon luminance, motion, orientation, or proximity. Across trials, the organization of stimuli was systematically decreased until perceived grouping became ambiguous. For all stimulus features, grouping ability remained relatively stable until 40°, beyond which thresholds significantly elevated. The pattern of change across eccentricity varied across stimulus feature, in which stimulus scale, dot size, or stimulus size interacted with eccentricity effects. These results demonstrate that perceptual grouping of such stimuli is not reliant upon foveal viewing, and suggest that selection of dominant grouping patterns from ambiguous displays operates similarly across much of the visual field.

Cortical magnification in human visual cortex parallels task performance around the visual field

“…3) parallels findings that they covary with eccentricity (35). Other tasks such as motion sensitivity (36), critical flicker frequency (37), texture segmentation (38,39) and perceptual grouping (40) do not show the same systematic decline with eccentricity as acuity. For these tasks, performance might be less tightly linked to V1 surface area.…”

“…Our finding that V1 surface area and acuity threshold covary with polar angle ( Figure 3 ) parallels findings that they covary with eccentricity ( Duncan and Boynton, 2003 ). Other tasks such as motion sensitivity ( McKee and Nakayama, 1984 ), critical flicker frequency ( Hartmann et al, 1979 ), texture segmentation ( Gurnsey et al, 1996 ; Barbot and Carrasco, 2017 ), and perceptual grouping ( Tannazzo et al, 2014 ) do not show the same systematic decline with eccentricity as acuity. For these tasks, performance might be less tightly linked to V1 surface area.…”

Cortical Magnification in Human Visual Cortex Parallels Task Performance around the Visual Field

“…3) parallels findings that they covary with eccentricity (35). Other tasks such as motion sensitivity ( 36), critical flicker frequency (37), texture segmentation (38,39) and perceptual grouping (40) do not show the same systematic decline with eccentricity as acuity. For these tasks, performance might be less tightly linked to V1 surface area.…”

Dependence of the filled-space illusion on the size and location of contextual distractors

“…A wide variety of other related factors were not accounted for in the model, which can significantly influence the assessment of the parameters of the cFSI. For example, complex processes of perceptual grouping in higher-order visual regions that likely affect the length judgements (Noguchi et al, 1990;Noguchi, 2003;Tannazzo et al, 2014) remained beyond the scope of the present modeling. Model calculations also did not concern the processes of spatial differentiation caused by two-dimensional spatial-frequency filtering, which occurs even at the lowest hierarchical levels of visual processing.…”