Disentangling encoding versus retrieval explanations of the bizarreness effect: implications for distinctiveness

Recall effects attributed to distinctiveness have been explained by both encoding and retrieval accounts. Resolution of this theoretical controversy has been clouded because the typical methodology confounds the encoding and retrieval contexts. Using bizarre and common sentences as materials, we introduce a paradigm that decouples the nature of the encoding context (mixed vs. unmixed lists of items) from the retrieval set (mixed vs. unmixed retrieval sets). Experiment 1 presented unmixed lists for study, and Experiment 2 presented mixed lists for study. In both experiments, significant bizarreness effects were obtained in free recall when the retrieval set intermixed items but not when the retrieval set consisted of only one item type. Also, Experiment 1, using a repeated testing procedure, did not reveal evidence for more extensive encoding of bizarre sentences than of common sentences. The results support the idea that retrieval dynamics primarily mediate the bizarreness effect, and perhaps more generally, distinctiveness effects.