The Influence of the Nature of Material and of Mental Operations on the Occurrence of the Bizarreness Effect

In the literature, a memory advantage for bizarre items over common ones has been found only in a few studies, especially with materials prepared ad hoc by the experimenter and with free recall rather than cued recall tests. These results contrast with the widespread conviction that bizarreness helps recall. The present paper explores the role of some variables involved in the “bizarreness” effect: (1) It examines the typical self-generation procedure in which the subject is asked to create an interaction between a pair of nouns, as well as the case in which only one noun is given. Higher freedom in generating sentences appears to correspond to higher free recall of bizarre items. (2) It is shown that bizarre items must be distinguished from “unusual” ones, which have different effects on memory. (3) By contrasting groups instructed to use either imagery or verbal elaboration, it is shown that the bizarreness effect is linked to the use of imagery. Instructions to use imagery without the possibility of creating bizarre representations do not improve the recall of common items. (4) The classification of parts of sentences generated reveals that, under common instructions, one subject's choice of verb and noun is more likely to be shared by other subjects. This fact may explain the different effects found by previous research in cued and free recall. (5) The overestimation of the recallability of bizarre items appears less evident than in previous research, probably because subjects had direct experience of the difficulties met in generating bizarre images.