Revisiting the retro-cue benefit: Why does focusing attention result in improved memory performance?

To investigate focused attention, most researchers have relied on the retro-cue paradigm, in which encoding of a memory set is followed by a retro-cue indicating the item to be tested. In this paradigm, it is typically observed that memory performance is enhanced for cued items compared to a no-cue control. Several mechanisms have been proposed to explain the retro-cue benefit; here we revisit two of them. To investigate whether the retro-cue protects from memory decay, we varied the time between encoding and the memory test using verbal (Experiments 1, 2, and 4) and visual memory materials (Experiment 3). To test whether the retro-cue protects from perceptual interference, we manipulated the presence of test-display interference using verbal (Experiment 5) and visual memory materials (Experiment 6). The retro-cue benefit was observed when test-display interference was present, or when there was time for decay after the onset time of the retro-cue in the cue and the control condition. When both were taken away or strongly minimized, the retro-cue benefit disappeared. Therefore, memory performance benefits from focused attention because focusing attention protects information from memory decay and from perceptual interference at test.