Abstract
The retrieval-practice paradigm has demonstrated that the act of selectively recovering some of the previously studied items from a category impairs the retrieval of the remaining items from that category, as compared to the retrieval of information from non-practiced categories (retrieval-induced forgetting); the practiced items are also better remembered than the items from non-practiced categories (a facilitation effect). This paradigm typically uses semantic categories, but its classic effects have been observed with other stimuli, such as lexical cues or ambiguous words. However, no study has tested this paradigm using ad hoc categories, a type of material that shares many characteristics with semantic categories; this was the goal of the present study. Our results replicated the facilitation effect, but we did not observe retrieval-induced forgetting. We discuss our results in light of the existing theories, suggest several factors that may underlie these results and propose future studies.