The replacement effect: Repeating some items while replacing others

We performed three experiments on recognition learning that tested for the existence of a replacement effect (i.e., the benefit accruing to nonrecognized items, or targets, when recognized items are replaced in the next study trial). A reverse Rock substitution procedure was used, and the replacement effect occurred in all three experiments. The results were interpreted in terms of a distributed memory model, the matched-filter model of Anderson (1973), but several modifications were necessary. The original version cannot learn, and a closed-loop modification did not show the repetition effect that was clearly evident in the data. The most satisfactory version was one based on probabilistic encoding of features in the item vectors, and it seemed capable of explaining most aspects of the data.