Continuation of work funded under EY 01128-07, on spatial, temporal and chromatic interactions in vision. Current emphasis is on theoretical and experimental studies of the mechanisms of spatio-temporal interaction, particularly retinal ones. The role of eye movements in perception is being studied by the technique of stabilizing the retinal image, and then introducing controlled image motion. We find that a number of global selectivity effects, formerly attributed to sensory pathways, are in fact due to eye movements. Other studies involved motion, masking effects and visual nonlinearities. We are also exploring the well-known pattern/flicker dichotomy by criterion-free psychophysical methods.