Abstract
The present study investigated mechanisms of transsaccadic object updating. We have previously shown that the pre-saccadic representation of the saccade target object is overwritten by its post-saccadic representation when visual stability is established (Tas & Hollingworth, ECEM 2019). However, other studies have shown that the pre- and post-saccadic representations are instead integrated across saccades (e.g., Wolf & Schutz, 2015). An important difference between these studies was the task instructions. In our previous experiments, we asked participants to report either the pre- or the post-saccadic feature of the saccade target. However, studies which found integration effects asked participants to report the feature of the target without specifying different states (pre-saccadic or post-saccadic) which may promote an integration mechanism. The present study tested this possibility. Participants executed a saccade to a colored disk. On half of the trials, the target’s color was changed by 15° during the saccade. After each trial, participants were asked to report the color of the target object by clicking on the corresponding color on a color wheel (integration block). Participants also completed two blocks where they saw the target either only pre-saccadically or only post-saccadically. Replicating our previous study, the response distributions of the integration trials were better fit by a bimodal than a unimodal model, providing evidence against integration. Further, participants consistently reported the post-saccadic color, indicating overwriting of the pre-saccadic color. Next, we tested whether integration trials resulted in better performance compared to the best single condition (pre-only or post-only block). We again found no evidence for integration: Color reports were not significantly more precise in the integration block compared to the best single performance. Together, these findings indicate that the visual system can keep the pre- and post-saccadic representations separate, and the pre-saccadic feature is often overwritten by the post-saccadic feature.