False recall with the drmrs ("drummers") procedure: a quantitative summary and review

In the Deese-Roediger-McDermott-Read-Solso (DRMRS) procedure, which has recently enjoyed widespread use, participants try to remember lists of items constructed around critical themes that are not presented. The purpose of this quantitative review was to estimate the extent to which these themes are falsely recalled (Critical Intrusions) and to compare this error rate with Correct Recall and with false recall of other words that were not presented (Noncritical Intrusions). Based on 111 estimates, the mean rate of Critical Intrusions was .374 (95% confidence interval of .344 to .403), which was a very large effect (d=2.40). Critical Intrusions were less frequent than Correct Recall (.572) but more frequent than Noncritical Intrusions (.078). Critical Intrusions were lower (.318) for people told to be confident (not to guess) than for people not so cautioned (.428), a medium to large effect size (d=0.69). Effects of other variables are summarized, and the theoretical and applied implications of these results are discussed.