Can We Process Information Without Encoding It into Working Memory?

Filtering is a cognitive mechanism that regulates how information is encoded into working memory. It minimizes the retention of irrelevant information while facilitating the maintenance of task-relevant information. While prior studies have examined the filtering of task-irrelevant distractors, it remains unclear whether information that needs to be briefly processed—but not maintained—can be partially filtered out. To address this, we developed a novel complex-span task involving three conditions: a pre-cue condition, where stimuli are identified as memory items or distractors before they are processed thus allowing for filtering; a retro-cue condition, where this information is given only after processing, preventing filtering; and a control condition without distractors. Across three experiments, memory performance in the pre-cue condition was comparable to the retro-cue condition but worse than the control condition. Additionally, using the Memory Measurement Model (Oberauer & Lewandowsky, 2019), we estimated the memory strength of distractors and found the same strength of distractors retained in working memory in both pre- and retro-cue conditions. These findings suggest that information requiring processing cannot be selectively filtered out during encoding into working memory.