Two processes are not necessary to understand memory deficits

Revisiting the remember-know task: Replications of Gardiner and Java (1990)

One of the most evidential behavioral results for two memory processes comes from Gardiner and Java (Memory & Cognition, 18, 23-30 1990). Participants provided more "remember" than "know" responses for old words but more know than remember responses for old nonwords. Moreover, there was no effect of word/nonword status for new items. The combination of a crossover interaction for old items with an invariance for new items provides strong evidence for two distinct processes while ruling out criteria or bias explanations. Here, we report a modern replication of this study. In three experiments, (Experiments 1, 2, and 4) with larger numbers of items and participants, we were unable to replicate the crossover. Instead, our data are more consistent with a single-process account. In a fourth experiment (Experiment 3), we were able to replicate Gardiner and Java's baseline results with a sure-unsure paradigm supporting a single-process explanation. It seems that Gardiner and Java's remarkable crossover result is not replicable.