PUB - Publikationen an der Universität Bielefeld

How is the assessment of location and length of visual stimuli affected by their eccentricity in the visual field? We report results of a study of this question in the context of perceptual comparison tasks. Based on the assumption that the perception of line segment end points is an essential prerequisite for length assess- ment and comparison, two experiments investigated if a correlation exists between peripherally perceived position and length. Our findings confirmed this correlation and supported a "decomposition" hypothesis: The assessment of a line segment can be formalised as the localisation of its end points (decomposition) and the computation of their distance to yield line segment length. An accordingly implemented, probabilistic computational model successfully reproduced the empirical findings and thus yielded further support for the proposed perception mechanisms.