Study effort versus distinctiveness in the recollection of veridical and illusory memories.

In past research, stimulus distinctiveness and study effort have been claimed to promote the development of distinctive memories, which in turn have been considered critical for enhancing veridical recollection and reducing illusory memory experiences. In the present investigation, stimulus distinctiveness, obtained by displaying text-redundant pictorial information at study, was pitted against study effort to determine whether either factor would be more beneficial to veridical recall and more detrimental to illusory recall than the other. Subjects first completed word fragments with or without the aid of an image of each word's referent and then performed a recall test. It was found that when images were useful to the encoding task (fragment completion), their presence at study enhanced veridical recall and reduced illusory memories more than any additional encoding effort.