Abstract
Human vision faces the challenge of producing a stable representation of the world given large distortions induced by eye movements. Alongside retinal displacement of a visual target goes a lack of sensitivity during saccades. Thus, it might not be surprising that trans-saccadic displacements of visual targets have been shown to go largely unnoticed. However, blanking the target for a few 100 milliseconds after a saccade facilitates the change detection for spatial features such as location or spatial frequency (Deubel, Schneider, & Bridgeman, 1996; Poth, Herwig, & Schneider, 2015). We investigated if this effect holds for non-spatial features, and if the potential increase in performance due to blanking can be predicted by pre- and post-saccadic discriminability separately. In the first experiment, we tested colour discrimination providing relevant visual input only in the periphery before a saccade or only in the fovea after a saccade. Participants had to judge whether the hue of a target stimulus was more red or blue than the average of all stimuli presented beforehand. Post-saccadic target presentation followed saccade initiation either directly or after a 200-ms blank. Based on pre- and post-saccadic discriminability we predicted the discrimination of trans-saccadic changes with or without blanking, as tested in the second experiment: Here, the coloured stimuli appeared both pre- and post-saccadically but changed their hue during the saccade to different degrees. Participants had to judge the difference between the pre- and post-saccadic stimulus. Again, a 200-ms blank could precede the post-saccadic stimulus or not. We found better change discrimination with blanking but this could not be predicted given the pre- and post-saccadic discriminability with and without blanking. In conclusion, the blanking effect might result from a modulation of the perceived common cause of the two visual inputs as suggested previously rather than from a modulation of feature discriminability.
Meeting abstract presented at VSS 2018