Differential effects of cue specificity and list length on the prospective and retrospective prospective-memory components

Event-based prospective memory (PM) refers to the ability to remember to perform an intended action at an appropriate moment that is indicated by some cue. It has been shown that increasing the number of PM cues as well as decreasing the cues' specificity can impair PM performance. Although both manipulations result in similar detrimental effects to PM accuracy, they may affect different underlying cognitive processes. To test this hypothesis, we manipulated both the number of cues and cue specificity and found the expected detrimental effects on PM accuracy. Analyses with the multinomial model of PM, which considers false PM responses and accounts for guessing biases, imply that the cue-list-length manipulation affected cue singularisation as well as intention retrieval, whereas cue specificity selectively affected intention retrieval. These results are original evidence that the performance decrements from the two manipulations have different cognitive underpinnings.