The bizarre imagery effect and intention to learn.

The bizarre imagery effect, better memory for bizarre stimuli than for common stimuli, is now an established finding. However, the mnemonic benefits of bizarre imagery are subject to several constraints (e.g., the use of mixed lists and free-recall tests). A further constraint on the bizarreness effect is demonstrated here. In each of two experiments, subjects were given either incidental or intentional study instructions and were asked to rate the vividness of the images they formed from the bizarre and common sentences. Contrary to conclusions based on available evidence, the bizarreness effect in free recall was manifested only with the incidental learning instructions. This additional constraint on the effect is consistent with the item-order account of bizarreness.