title: Noise-enhanced target discrimination under the influence of fixational eye movements and external noise.
abstract: Active motor processes are present in many sensory systems to enhance perception. In the human visual system, miniature eye movements are produced involuntarily and unconsciously when we fixate a stationary target. These fixational eye movements represent self-generated noise which serves important perceptual functions. Here we investigate fixational eye movements under the influence of external noise. In a two-choice discrimination task, the target stimulus performed a random walk with varying noise intensity. We observe noise-enhanced discrimination of the target stimulus characterized by a U-shaped curve of manual response times as a function of the diffusion constant of the stimulus. Based on the experiments, we develop a stochastic information-accumulator model for stimulus discrimination in a noisy environment. Our results provide a new explanation for the constructive role of fixational eye movements in visual perception.
authors.affiliation: Department of Psychology and Interdisciplinary, Center for Dynamics of Complex Systems, University of Potsdam, Potsdam, Germany. christian.starzynski@uni-potsdam.de
authors.forename: Christian
authors.initials: C
authors.lastname: Starzynski
authors.forename: Ralf
authors.initials: R
authors.lastname: Engbert