Retrieval in prospective memory: Multiple processes or just delay?

In prospective memory (PM) research, a common finding is that PM accuracy is greater using focal, rather than nonfocal, cues. Under the multiprocess framework, the high PM performance for focal cues (cues that facilitate noticing of the target), often in the absence of task interference, reflects people’s ability to rely on spontaneous retrieval processes. By contrast, nonfocal cues (cues that do not facilitate noticing) require monitoring. A competing explanation suggests that a single process underlies focal versus nonfocal PM: People adjust their delay in ongoing responding to allow enough time for PM information to reach awareness (delay theory). Participants’ lower nonfocal performance arises because they fail to delay responding to a sufficient degree; with focal cues, the PM information accumulation rate is fast enough that no delay is necessary (and thus most everyone performs well). We sought to improve nonfocal PM performance by pairing a PM task with fast information accumulation to an ongoing task for which the requisite information accumulated more slowly. Reasoning from delay theory, we expected PM accuracy levels in this nonfocal PM task to approximate that observed in a focal PM task (for which the PM tasks were identical). In contrast to this expectation, the focal condition displayed significantly higher PM accuracy (despite demonstrating a reliably shorter response delay). In light of these findings, we concluded that the multiprocess interpretation is favoured.

Prior Task Experience and Comparable Stimulus Exposure Nullify Focal and Nonfocal Prospective Memory Retrieval Differences

We explored the nature of focal versus nonfocal event-based prospective memory retrieval. In the context of a lexical decision task, people received an intention to respond to a single word (focal) in one condition and to a category label (nonfocal) for the other condition. Participants experienced both conditions, and their order was manipulated. The focal instruction condition was a single word presented multiple times. In Experiment 1, the stimuli in the nonfocal condition were different exemplars from a category, each presented once. In the nonfocal condition retrieval was poorer and reaction times were slower during the ongoing task as compared to the focal condition, replicating prior findings. In Experiment 2, the stimulus in the nonfocal condition was a single category exemplar repeated multiple times. When this single-exemplar nonfocal condition followed in time the single-item focal condition, focal versus nonfocal performance was virtually indistinguishable. These results demonstrate that people can modify their stimulus processing and expectations in event-based prospective memory tasks based on experience with the nature of prospective cues and with the ongoing task.

A Comparison of Transfer-Appropriate Processing and Multi-Process Frameworks for Prospective Memory Performance

We examined multi-process (MP) and transfer-appropriate processing descriptions of prospective memory (PM). Three conditions were compared that varied the overlap in processing type (perceptual/conceptual) between the ongoing and PM tasks such that two conditions involved a match of perceptual processing and one condition involved a mismatch in processing (conceptual ongoing task/perceptual PM task). One of the matched processing conditions also created a focal PM task, whereas the other two conditions were considered non-focal ( Einstein & McDaniel, 2005 ). PM task accuracy and ongoing task completion speed in baseline and PM task conditions were measured. Accuracy results indicated a higher PM task completion rate for the focal condition than the non-focal conditions, a finding that is consistent with predictions made by the MP view. However, reaction time (RT) analyses indicated that PM task cost did not differ across conditions when practice effects are considered. Thus, the PM accuracy results are consistent with a MP description of PM, but RT results did not support the MP view predictions regarding PM cost.