Abstract
Introduction. Human vision is characterized by consistent shifts between fixations and saccadic eye movements. With each saccade, internal object representations change their retinal position and spatial resolution which raises the question as to how extra-foveal perception is affected by upcoming saccadic eye movements. Recently, we suggested that saccades are accompanied by a prediction of their perceptual consequences—i.e., the foveation of the target object (Herwig & Schneider, 2014, Journal of Experimental Psychology: General). Accordingly, extra-foveal perception should be biased toward previously associated foveal input. Up to now, effects of transsaccadic feature prediction on extra-foveal perception have been exclusively reported for surface features (i.e., color and spatial frequency) which are known to play an important role in establishing object correspondence while moving the eyes. In the present study, we tested whether also the extra-foveal perception of visual shape is partly based on predicted postsaccadic foveal input. Methods. Sixteen participants in an eyetracking experiment first underwent a 30 min acquisition phase, where, unnoticed by most participants, one out of two objects systematically changed its shape during saccades. In the following test phase, participants had to judge the shape of briefly presented peripheral saccade target objects. Results. Peripheral saccade targets were perceived as less curved for objects which previously changed from more circular in the periphery to more triangular in the fovea compared to objects which did not change during acquisition. Likewise, shapes were perceived as more curved for objects which previously changed from triangular- to circular-like. Conclusion. This result indicates that the extra-foveal perception of shape is specifically biased toward previously associated postsaccadic foveal input. Thus, extra-foveal perception seems to depend not solely on the current input but also on memorized experiences enabling predictions about the perceptual consequences of saccadic eye movements.
Meeting abstract presented at VSS 2015