Sequential effects in continued visual search: Using fixation-related potentials to compare distractor processing before and after target detection


  • This study was supported by grant P 22189-B18 of the Austrian Science Fund (FWF), a grant from the European Union within the 6th Framework Programme (Project 517590; EYE-to-IT), and by a grant of the state government of Styria (Project PN 4055; NeuroCenter Styria).


To search for a target in a complex environment is an everyday behavior that ends with finding the target. When we search for two identical targets, however, we must continue the search after finding the first target and memorize its location. We used fixation-related potentials to investigate the neural correlates of different stages of the search, that is, before and after finding the first target. Having found the first target influenced subsequent distractor processing. Compared to distractor fixations before the first target fixation, a negative shift was observed for three subsequent distractor fixations. These results suggest that processing a target in continued search modulates the brain's response, either transiently by reflecting temporary working memory processes or permanently by reflecting working memory retention.