Encoding strategy changes and spacing effects in the free recall of unmixed lists

Memory for repeated items often improves when repetitions are separated by other items—a phenomenon called the spacing effect. In two experiments, we explored the complex interaction between study strategies, serial position, and spacing effects. When people studied several unmixed lists, they initially used mainly rote rehearsal, but some people eventually adopted relational encoding strategies like creating a story from the items (Experiment 1). We observed overall spacing effects when participants used the story mnemonic, but not when they employed rote rehearsal strategies (Experiments 1 and 2). This occurred in part because the story mnemonic reduced or eliminated the usual recall advantage of immediately repeated items at the beginning of lists (Experiment 2).