Abstract
Working memory enables one to actively maintain a limited number of sensory inputs for immediate responses. While multiple items can be simultaneously maintained, there also exist several mechanisms to prioritize a subset of working memory. Those prioritized items are more robust to perceptual interference than deprioritized items. The present study investigated how different types of prioritization mechanisms interact with perceptual interference by external stimuli. In our experiment, two groups of participants were required to memorize colored shapes. A group of participants (value-based prioritization) were informed that one of the memory items was more valuable than the rest, while the other group was instructed that cued memory item would be the most likely to be probed (cueing-based prioritization). After the memory display presentation, a to-be-ignored suffix item, a geometric shape, was presented or absent. In this way, we tested whether the magnitude of suffix interference would vary depending on the mechanisms of prioritization in working memory. As results, the patterns of suffix interference differed, depending on the types of prioritization. Specifically, the magnitude of the interference was larger for prioritized items than deprioritized items when a high value was assigned proactively to the items, p = .035. By contrast, when the value-based prioritization applied retroactively, suffix interference was found for deprioritized items, p = .007, but not for prioritized items. When an item in working memory was prioritized by a spatial cue, suffix interference for prioritized items was not found, regardless of whether the prioritization was provided proactively or retroactively. The suffix item interfered with memory probe performance only for proactively non-cued deprioritized item, p < .001. These findings suggest that two forms of prioritization in working memory interacted differently with to-be-ignored perceptual interference. This dissociation implies that working memory items prioritized by their potential value has a more privileged state.