To forget or not to forget: the effect of probability of test on directed forgetting.

Two experiments investigated how individuals use explicit memory cues that designate different probabilities of test. As in typical directed forgetting studies, subjects received words explicitly cued as having either a 0% or a 100% chance of being on a subsequent memory test (i.e. forget and remember cues, respectively). In addition, some words were explicitly cued as having the potential to be either forgotten or remembered (i.e. a 50% cue). Recall of 50% words was between that of 0% and 100% words. In addition, the presence of 50% words lowered recall of the 100% words compared to that of a control group that did not receive 50% words, but received the same number of 100% words. A think-aloud task indicated that these results were due to 50% words being treated like either 100% of 0% words at encoding. The results are discussed in terms of the effect of different probabilities of test on the strategic processing and representation of information.