Dynamic integration of salience and value information for saccadic eye movements A Schütz |
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Department of Psychology, Justus-Liebig-University Giessen, Germany
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| Humans shift their gaze to a new location several times per second. Fixation behavior is influenced by the low-level salience of the visual stimulus, such as luminance and color, but also by high-level task demands and prior knowledge. Under natural conditions, different sources of information might conflict with each other and have to be combined. In our paradigm [Schütz et al, 2012, PNAS, 109(19), 7547-7552], we traded off visual salience against expected value. To manipulate salience, we varied the relative luminance contrast of two adjacent regions. To manipulate value, we varied the amount of reward and penalty. In a salience baseline condition, we instructed subjects to make saccades to the regions, without reward or penalty. In the easy value condition, subjects won money for landing on one region. In the difficult value condition, subjects additionally lost money for landing on the other region. We show that salience and value information influenced the saccadic end point within the regions, but with different time courses. Short-latency saccades were determined by salience, but value information was taken into account for long-latency saccades. We present a model that describes these data by dynamically weighting and integrating detailed topographic maps of visual salience and value. |
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