Are human scanpaths Levy flights?

Introduces a phenomenological model for the generation of human scanpaths. Scanpaths, the succession of rapid eye-movements (saccades), are treated as realizations of a stochastic process in a random quenched saliency field with prespecified covariance structure. Efficiency of the process is defined in terms of convergence properties of the time dependent probability of fixating a region in the visual environment. The authors´ analysis is based on the assumption that the visual system minimizes the typical time needed to process a visual scene. This type of temporal optimization implies that scanpaths are geometrically similar to a prominent class of random walks known as Levy flights. Furthermore, the authors show that scanning strategies with a Levy statistic are orders of magnitude more robust against statistical variations in the saliency field. The theory is well confirmed by preliminary psychophysical experiments