The consequences of preparing for informative or distracting stimuli.

How do individuals prepare for impending distractors? It has been recently suggested that not only observers do not inhibit distractors before their appearance, but they are rather more alert at those moments. Interestingly, a similar effect emerged when observers prepared for task-relevant, informative stimuli, supporting a mandatory "attend-all" mechanism. However, the preparation effect was only demonstrated in speeded dot-probe tasks, and it is yet to be determined whether preparing for distractors merely facilitates motor preparation or extends to other outcomes, such as modifying early visual processes. In two experiments, we replaced the dot-probe task with a four-letter memory encoding task. Participants performed a change detection task that included Informative-display, Distractors-display, and No-display blocks. These displays appeared during the retention interval of the change-detection task. To probe attention, in 25% of the trials, four letters were displayed at the exact moment in which the Informative/Distractors display was expected, and participants were required to remember as many letters as possible. As expected, the performance in the change-detection task was best at the Informative- and worst at the Distractors-display condition. Importantly, participants recalled more letters when they appeared during the anticipation for both informative and distracting stimuli, and no meaningful difference was observed between these conditions. These findings suggest that the preparation effect extends beyond motor preparation, influencing visual processes at an early stage. They also support the notion that the preparation effect is not very flexible, yet further research is required to confirm this conclusion.