The temporal dynamics of global-to-local feedback in the formation of hierarchical motion patterns: psychophysics and computational simulations
Four motion quartets, each ambiguous with respect to the perception of parallel-path horizontal or vertical motion, were arranged
in a diamond configuration. Both global parallel-path motion (the same motion axis for all the quartets), which is typical
for multiquartet stimuli, and global rotational rocking are perceived. Experiment 1 indicated that rotational rocking is established at different levels of processing. Globally, larger displacements of each
quartet’s elements increase the angle of rotation and, thereby, the perception of rotational rocking. Locally, larger displacements
have the opposite effect, weakening motion percepts. Experiment 2 showed that global-to-local feedback affects the local perception of rotation-consistent versus rotation-inconsistent motion
directions. Experiment 3 provided evidence for hysteresis effects indicative of competition between global rotational rocking and parallel-path motion.
The experimental results were simulated by a two-level dynamical model incorporating global-to-local feedback, with recurrent
feedforward/feedback loops creating detection instabilities that amplify activation at both global and local levels of the
rotational-rocking pattern.