Task-irrelevant memories rapidly gain attentional control with learning.

Although many of our perceptual biases stem from long-term, repeated exposure, current theories of visual search assume a central role for visual working memory (VWM) in guiding attention to target information. Crucially, whether a VWM representation guides attention depends on the relative priority that the memory has within VWM. Here, in a combined visual search/VWM task, we used attentional guidance by irrelevant memories to measure how long a target representation remains prioritized in VWM when observers repeatedly search for the same target. Irrelevant memories started guiding attention already when the target was repeated once, indicating that the target representation rapidly lost priority within VWM as it moved to long-term memory. By showing that training can lead to interference from irrelevant memories, the findings resolve a long-standing paradox on why VWM appears central to, yet at the same time not sufficient nor necessary for attentional guidance.