The ecology of gaze shifts

We present a phenomenological model for the generation of human visual scanpaths, Successions of saccadic eye movements are treated as realizations of a stochastic jump process in a random quenched salience field. Efficiency of the process is defined in terms of convergence properties of the time-dependent probability of fixating a region in the visual environment. Based on the assumption that the visual system minimizes the typical time needed to process a visual scene, our theory predicts that scanpaths are geometrically similar to a prominent class of random walks known as Levy flights. The theory is well confirmed by psychophysical experiments. (C) 2000 Elsevier Science B.V. All rights reserved.