Prospective Memory: The Delayed Realization of Intentions
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task accuracies and latencies would have been bimo-relatively automatic or strategic. For example, automatic dal, with participants who monitored having a lower or strategic processes thought to underlie recognition average accuracy and a higher average latency than memory (e.g., Mandler, 1980; Sternberg, 1969) could participants who did not monitor. Neither frequency play a role. Alternatively, some aspect of memory re-distribution appeared to be bimodal, however, con-trieval as postulated by the Automatic Associative sistent with the expectation that participants main-Activation view or the Noticing + Search view (Einstein tained the cognitive system in a prospective memory & McDaniel, 1996) could be the process by which the retrieval mode (or maintained an increased level of ac-evaluation is made. Finally, to the extent that the ACT tivation of the prospective memory representation) architecture (J. R. Anderson, 1983) can account for but did not check for the target events on alternating strategic monitoring, the firing of production rules control trials. could explain the process of checking. Although these A significant difference in prospective memory various possible conceptions of the checking process accuracy or latency was not expected (and was not allow that checking may be automatic or strategic, the obtained) as a function of whether the experimental and reaction time task costs on experimental trials relative control trials alternated or were blocked. The two-to alternating control trials in the current experiment process view of strategic monitoring, as well as the suggest that checking was relatively strategic, at least alternate one-process views, predict that strategic in the current experiment. monitoring should be equivalent on the alternating and blocked experimental trials. The views make different predictions only with regard to the processes that ALTERNATE ONE-PROCESS should be involved on the alternating versus blocked INTERPRETATIONS control trials, where prospective memory cannot be measured (i.e., because there is no prospective memory Although the two-process monitoring view provides a task on control trials). compelling explanation of the current results, the results are open to alternate one-process interpretations. One possibility is that the costs on the experimental trials CHECKING and the alternating control trials relative to the blocked control trials reflect only a process of maintaining a The current experiment was not designed to test alter-retrieval mode (or activation): Participants maintained a nate conceptions of the checking process, but several retrieval mode (or activation) to a greater extent on possible conceptions are outlined here. Depending on experimental trials than alternating control trials, and to the characteristics of the prospective memory task, the a greater extent on alternating control trials than blocked cover task in which it is embedded, and the individual control trials, where they were not expected to maintain doing the strategic monitoring, the process of directing a retrieval mode at all (or at least to a much lesser extent). attention to the stimuli could be controlled by the envi-This seems unlikely, because research has suggested ronment and be relatively automatic or reflexive on the that a retrieval mode or an increased level of activation part of the individual (e.g., an exogenous orienting re-persists as long as the goal to perform the retrieval task sponse; Lauwereyns, 1998), or instead it could be con-exists, and there was no reason to expect that a retrieval trolled by the individual or a SAS or other type of mode or activation on alternating control trials would executive attentional system (e.g., an endogenous ori-be maintained to a lesser extent than on experimental enting response; Lauwereyns, 1998). Alternatively, trials. some aspect of automatic memory retrieval, such as Another possibility is that the costs on the automatic associative retrieval of the intended action, experimental trials and the alternating control trials which results from conscious processing of the target relative to the blocked control trials reflect only a event with which it was associated at encoding (as pos-process of checking: Participants checked for the target tulated by the Automatic Associative Activation view events to a greater extent on experimental trials than of prospective memory; Einstein & McDaniel, 1996), or on alternating control trials, and to a greater extent on a feeling of familiarity or significance for the target event alternating control trials than on blocked control trials, that causes the target event to be noticed (as postu-where they were not expected to check at all. This lated by the Noticing + Search view of prospective seems unlikely, because checking was costly, and a memory; Einstein & McDaniel, 1996), could direct at-signal was given to indicate that no target event would tention to the stimuli. appear on the control trials and that checking was The process of evaluating whether a stimulus is a therefore unnecessary, so there was no reason to retrieval cue for an intended action could also be expect checking on any control trials.
make a telephone call once a day for 5 days when they the two paradigms. Specifically, the exact motoric re-associated the activity with other routine daily events quirements of many naturally occurring intentions (so-called "conjunction" cues) than when internal or (e.g., "buy birthday present") may not be sufficiently other external cues (e.g., diaries) were used. The exact well specified at encoding (or throughout the role of daily structure in the fulfilment of delayed retention interval), to allow the representation of these intention tasks in young and older adults remains to be activities to benefit from the kind of preparatory established, however, particularly as Maylor's study did processing that we have argued supports the not include a comparison of the use and effectiveness representation of more well-defined (laboratory-based) of conjunction cues between these two age groups. It actions. Indeed, not all naturally occurring intentions is interesting to note in this regard that an attempt has involve action-based responses. Some of the activities been made to enhance older adults' prospective memory generated by participants in the prospective and performance in a laboratory setting by using tasks that retrospective fluency tasks, for example, could be are intended to mimic the richness and structure of daily classified as involving primarily verbal responses life events (e.g., Rendell & Craik, 2000). Age-related (e.g., to have a conversation with someone or to pass declines have still been obtained under these conditions, on a message), while others represent purely thought-however, perhaps because the tasks are not readily able based or cognitive tasks (e.g., "choose holiday to capture or recreate the familiarity and personal destination"). The exact role of preparatory motoric relevance of the individuals' own routines. processing in successful prospective remembering remains to be established, however, as laboratory Intention-superiority effects for naturally studies of the ISE have typically used experimenter-occurring and laboratory activities initiated retrieval, which removes the need for participants to remember to carry out the actions for The current findings reveal a clear age-associated themselves when a designated retrieval context impairment in the ability to access naturally occurring arrives. intentions in a speeded fluency task undertaken during the retention interval between intention formation and Conclusion completion. This is in contrast to the findings of Freeman and Ellis (in press-b), which demonstrated an equivalent In summary, this study revealed a clear age-related de-advantage for to-be-enacted laboratory-based actions cline in the ability to access intention representations over actions not intended for enactment in young and prior to completion, with more intended activities failing healthy older adults. We have argued elsewhere (e.g., to come to mind in the prospective fluency task for older Freeman & Ellis, in press-a) that there may be similarities adults than for young adults. There was no apparent between the advantage for to-be-enacted laboratory-age difference in the inaccessibility (or inhibition) of based actions and the advantage that is frequently already completed intentions, however, with both age observed for verbally presented action words that have groups demonstrating evidence of an intention-been enacted during encoding (the subject-performed completion effect. Despite reduced intention task effect; Cohen, 1981). More specifically, the accessibility during the retention interval, older adults intention-superiority effect for simple motor actions reported having carried out more of their intended intended for enactment after a short delay might reflect activities during the week than did young adults. the operation of covert motoric or SPT-type encoding Interestingly, this appeared to be the case primarily for or rehearsal operations aimed at preparing these actions intentions for which no specific retrieval aids had been for imminent execution. These could include operations used. One possibility is that older adults may for setting the parameters of the action schema to be compensate for impaired intention accessibility by executed in terms of its duration, direction, and force. relying more on the ongoing sequence of daily routine The absence of an age difference in the accessibility of events to support intention retrieval and execution. This laboratory-based intentions mirrors the finding of is consistent with the observation of an age-related reduced age-related declines in memory for SPTs and increase in the temporal organization of activities pro-suggests that covert motoric processing may be duced in the prospective fluency task. In line with this, undertaken relatively automatically for this type of while there was a correlation between intention acces-material. sibility and intention completion in young adults, sug-The apparent discrepancy between age differences gesting a role for the intention-superiority effect in in the ISE for naturally occurring and experimental prospective memory performance in this population, intentions might therefore reflect a fundamental there was no evidence of this relationship among older difference in the nature of the activities involved in adults.
