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 eld. EEciency of the process is deened in terms of convergence properties of the time dependent probability of xating 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 L evy ights. The theory is well connrmed by psychophysical experiments.