Spotlight on the past: Focusing attention on long-term memory

Eight experiments tested the common idea that memory retrieval is attention turned inward by adapting a perceptual attention task to short-term and long-term memory paradigms to measure the focus of attention on memory. The resulting position-cued recognition task produces a distance effect that defines the sharpness of the focus of attention on memory. In theory, the effect depends on the similarity of memory probes to the cued item and its neighbors on the list and not the memory store that holds the list. The experiments asked whether the focused-attention distance effect would be observed in both long-term and short-term memory paradigms. Experiments 1-3 defined long-term memory operationally as "that which survives distracting tasks" and found distance effects after two, four, or six distracting arithmetic problems that were similar to distance effects with no distraction. Experiments 4-6 defined long-term memory operationally as "that which was trained" and found distance effects after 0, 10, and 20 pre-training trials that were similar to distance effects with novel items. Experiments 7 and 8 defined long-term memory operationally as "that which contains pre-experimental knowledge," and found distance effects when subjects recognized probe letters in spoken words and in the names of pictures they identified. The results support the hypothesis that retrieval from short-term and long-term memory both require attention turned inward. They support the hypothesis that attentional selection, turned inward or outward, depends more on the similarity structure of the list and the probe than the memory store that holds the list.