Abstract
Perceptual processes in human observers vary considerably across a number of domains, producing idiosyncratic biases in the appearance of ambiguous figures [1], faces [2], and a number of visual illusions [3-6]. This work has largely emphasized object and pattern recognition, which suggests that these are more likely to produce individual differences. However, the presence of substantial variation in the anatomy and physiology of the visual system [4,7,8] suggests that individual variations may be found in even more basic visual tasks. To support this idea, we demonstrate observer-specific biases in a fundamental visual task - object localization throughout the visual field. We show that localization judgments of briefly presented targets produce idiosyncratic signatures of perceptual distortions in each observer and suggest that even the most basic visual judgments, such as object location, can differ substantially between individuals.