The phenomenon of the wandering point on a blank sheet of paper in serial reproductions is the starting point of an investigation of the perceptual field structure of homogeneous stimulus areas; 609 stimulus points distributed regularly in 21 rows and 29 columns on a DIN A4 sheet were presented successively to 10 subjects and had to be reproduced immediately afterwards in order to establish empirical vector fields. These were subjected to vector-analytic procedures. A method for the decomposition of the measured vector fields into partitions from gradient potentials and circulation potentials is demonstrated. The gradient potentials of the empirical vector fields revealed a highly regular structure with four point attractors near the corners of the sheet. A model calculation of the wandering point in this potential landscape showed results comparable to the empirical phenomenon. The results are discussed in favor of Gestalt theory and against direct perception.
Perceptual multistability refers to cases where perception alternates between two or more interpretations of an unchanging sensory stimulus. In a first experiment we trained eight pigeons to discriminate horizontal and vertical apparent motion stimuli and then presented a multistable display. In five cases their behavior showed alternations similar to human experiments. In a second experiment we varied the aspect ratio of the display in order to support the hypothesis of a percept-driven nature of the switching behavior. The pecking rates and mean phase durations varied as predicted. This is the first evidence of visual multistability in animals confronted with classical ambiguous figures. The data suggest a stochastic mechanism.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.