The role of rehearsals in self-generated prospective memory tasks.

In order to inquire into the nature of retrieval in prospective memory in a naturalistic context, we investigated the number and circumstances of rehearsals of different kinds of intentions to be pursued during a single time period. Thirty-six students were given four minutes to generate a list of tasks they were planning to perform over the course of 10 days. During this retention interval, they were provided with pocket-size diaries in which they recorded the details of each occasion they thought about the tasks previously listed. As to the nature of any triggers or cues that prompted rehearsal, the participants were asked to choose one of three alternatives: (1) association with an internal or an external cue that accidently appeared in the surroundings (accidental rehearsals), (2) deliberate thinking, e.g. while planning (self-initiated rehearsals), (3) recollection that spontaneously popped into one's mind for no apparent reason (no-trigger rehearsals). The results showed that thoughts about intended actions appeared more often after accidental cues than for no apparent reason. However, the relative contribution of self-initiated triggers to the rehearsal process was substantial: Most importantly, it was the self-initiated rehearsal that differentiated between executed and unexecuted actions. In addition, the most activated intention resulted in a higher frequency of no-trigger and self-initiated rehearsals than the remaining intentions. Finally, perceived intention importance was positively related to both the number of rehearsals and the likelihood of successful task completion. The results are discussed with regard to which factors may be crucial for the successful performance of participants' own self-generated intentions in a natural setting. The role of deliberate rehearsal in specifying the details of the intended action and its designated retrieval context is highlighted.