Subjects’ estimation of the eccentricity of stationary targets in the peripheral field often exhibits systematic biases. In collaboration with Lynn Robertson’s group, we characterized the influence of visual boundaries on these localization biases and discovered fundamental differences between intrinsic boundaries (the edges of the visual field) and external boundaries (the nose, brow, or experimentally imposed boundaries) (Fortenbaugh et al., 2012). Specifically, we observed peripheral localization biases when the visual field was not bounded by external borders but foveal biases when external boundaries were present.
In another study, we demonstrated that known perceptual asymmetries in visual perception between the upper and lower visual field can be fully accounted for by individual differences in the shape of each participant’s visual field. Those subjects with more symmetric visual field extents in the upper and lower visual field demonstrated a weaker perceptual asymmetry for stimuli presented to the upper versus lower visual field (Fortenbaugh et al., 2015). The results reveal important influences of visual field boundaries on visual perception, even for visual field locations far from those boundaries. Based on our findings, we propose a new metric for representing the eccentricity of visual field locations that is based on the percentage of visual field extent for a given location, as opposed to the conventional metric of degrees of visual angle in a polar coordinate system.