Abstract
Our perception of the world around us appears stable and continuous despite rhythmic interruptions in the form of saccadic eye movements. This apparent stability is achieved by integrating percepts from before and after a saccade in a seamless fashion. There is evidence that this trans-saccadic integration is predictive, in the sense that the visual system may anticipate what will appear in the fovea based on a peripheral preview. Here, we investigated to what extent this mechanism is predictive in terms of current notions of predictive processing and predictive coding. In Experiment 1, we investigated whether trans-saccadic integration flexibly adjusts to environmental contingencies as would be expected from a predictive process. We measured trans-saccadic integration in the form of a behavioral preview effect with face stimuli in a gaze-contingent experimental design. Participants made cued saccades to peripheral stimuli. During the saccade, the face could change its orientation (upright-to-inverted/inverted-to-upright) or remain the same. In addition, the post-saccadic target face exhibited a slight tilt. The task was to discriminate whether the target face tilt was to the left or to the right. A strong preview effect demonstrated better post-saccadic face tilt discrimination when the face remained the same compared to when it changed. Crucially, this preview effect could be modulated by a preceding training period with 100% change versus 100% no-change trials. A single-trial, mixed-model analysis showed that the effect continued to adapt to statistical regularities after the training session. In Experiment 2, we investigated the neural basis of the preview effect with combined MEG and eye-tracking in a similar experimental design. Fixation-related field results show that the neural basis of the behavioral preview effect exhibits properties of a prediction error signal and suggests that certain stages of trans-saccadic integration can be interpreted in terms of predictive coding.