Eye Movements, Visual Perception and Attention

During visual fixation, small eye movements of which we are usually not aware, prevent the
maintenance of a steady direction of gaze. These eye movements are finely controlled and
shift retinal projection of objects within the fovea, the region of the retina where visual
acuity is highest. This program of research examines the link between these eye movements and
attention, and tests the hypothesis that attention, similarly to eye movements, can be
controlled at the foveal level. Psychophysical experiments with human subjects, using
state-of-the-art techniques, high resolution eyetracking and retinal stabilization are
conducted to address these questions. Gaze-contingent calibration procedures are employed to
achieve high accuracy in gaze localization. A custom developed gaze-contingent display is
used to shift in real-time visual stimuli on the monitor to compensate for the observer eye
movements during fixation periods and to maintain stimuli at a desired location on the
retina. Experiments involve visual discrimination/detection tasks with stimuli presented at
selected eccentricities within the fovea. Participants' performance and reaction times are
examined under different conditions, in which various types of attention are manipulated. In
addition to advancing our basic understanding of visual perception, this research leads to a
better understanding of attentional control at the foveal scale and of the contribution of
microscopic eye movements to the acquisition and processing of visual details.