Abstract
Accurately perceiving the positions of objects is a critical visual function. Recent research demonstrated that observers consistently mislocalize brief objects throughout the visual field in an idiosyncratic manner: observes mislocalize objects in different ways in different parts of the visual field (Kosovicheva & Whitney, 2017). One possibility is that these fingerprints of distorted space perception are related to differences in the resolution of position coding throughout the visual field. If so, there may be systematic differences in acuity throughout the visual field that correlate with the mislocalizations. Here, we tested this. In a first experiment, we constructed localization bias maps throughout the visual field for individual observers. Observers were asked to localize a brief noise patch target with a mouse cursor. The possible target locations covered much of the visual field. Mislocalization (constant) errors were recorded and found to be significant and idiosyncratic, such that each observer mislocalized targets consistently in a unique way throughout the visual field. Because of the mislocalizations, there were some regions of the visual field that were effectively compressed (sinks) and other regions that were expanded (sources). In a second experiment, we tested whether these individualized perceptual distortion maps correlated with differences in visual resolution. We tested Vernier acuity thresholds at 6 locations in each observer’s visual field, specifically 4 in the compressed and expanded regions identified in the first Experiment and 2 in neutral regions. Interestingly, we found significantly higher acuity in perceptually compressed regions than in the expanded regions. The results reveal a primitive inhomogeneity in the spatial resolution of position coding, which may then bias assigned object position. This inhomogeneity indicates that our visual system evidently has a compensatory mechanism to correct the individualized biases, to establish an accurate and stable position representation that is ultimately consistent between observers.