Apparent motion path composed of a serial concatenation of translations and rotations

Foster's two schemes with respect to preferred paths in visual apparent motion were tested in conditions in which large differences in orientations and symmetry between the inducing stimuli resulted in large differences in the predicted apparent motion paths. The results showed that under these conditions the measured apparent motion paths were far apart from the separate theoretical curves of the two schemes, especially in describing the dependence of object orientation on horizontal position. The present evidence seem to suggest that Foster's two schemes may be applied to the description of the apparent motion between objects differing greatly in orientation and positional symmetry, provided that the two schemes are concatenated serially: i.e. translations first, then rotations.