Complex Prospective Memory and Executive Control of Working Memory: A Process Model

Summary Recent research on prospective memory suggests the involvement of executive functions in explaining performance in complex task environments. However, few theoretical concepts specify which executive functions contribute to prospective memory performance. Moreover, it is unclear which executive functions are required in the course of the prospective memory process. Therefore, we argue that prospective memory should be conceptualized as a multi-phasic process and propose a theoretical model that disentangles four different phases: (a) forming an intention, (b) maintaining the intention, (c) initiating the intended action, and (d) executing the intention. Empirical tests of the model with eighty adults reveal that more than 50 percent of the variance in the complex prospective memory task is predicted by the executive measures. Of those, planning and cognitive flexibility are particularly important predictors. The discussion focuses on the role of particular executive functions in predicting performance in specific phases of prospective remembering. Key words: prospective memory, executive functions, planning, cognitive flexibility, inhibition, working memory According to Neisser (1982), "to remember" stands for two different everyday cognitive processes: "remembering what we must do" and "remembering what we have done. " The current literature refers to the first type of remembering as prospective memory and to the second as retrospective memory (Einstein & McDaniel, 1990, 1996). Although its proper labeling is still under discussion (Burgess, 2000; Crowder, 1996; Ellis, 1996; Goschke & Kuhl, 1996), the field of prospective memory research "is booming" (Roediger, 1996, p. 149; cf also Ellis & Kvavilashvili, 2000). Interest in prospective memory is largely based on its relevance in everyday life, for example having to remember to attend a meeting, to buy a certain item in the grocery store, or to manage the various daily tasks at home and at work. The cognitive mechanisms underlying prospective memory performance have become an issue of major interest. In searching for processes explaining differences in prospective remembering, some researchers have focused on processes related to retrospective memory (e.g., recency and proximity effects; Hitch & Ferguson, 1991). The general hypothesis of many studies was that, in principle, prospective memory performance can be explained by the same mechanisms underlying performance in well-known retrospective memory tasks such as delayed recall (Crowder, 1996). In more recent work, the impact of another memory process, i.e., working memory, has been investigated. Consistently, and with different prospective tasks, these studies report that working memory capacity predicts significant amounts of the variance in prospective memory performance (e.g., Cherry & LeCompte, 1999; Kliegel, McDaniel & Einstein, 2000; Martin & Park, 1999). In sum, some parts of the existing literature suggest that processes related to retrospective memory performance explain differences in prospective memory performance. However, this conclusion might be premature for two reasons. First, most empirical studies report only weak relations between retrospective memory processes and prospective memory performance (Cockburn, 1995; Einstein, Holland, McDaniel & Guynn, 1992; Einstein & McDaniel, 1990; Kliegel et al., 2000; Kvavilashvili, 1987). Second, task analyses of everyday prospective memory suggest that prospective remembering requires more than just retrospective memory. In fact, it seems obvious that in everyday life one typically works on several "subtasks" in order to perform well on an everyday prospective memory task: One has to form an intention, one has to keep the intention in mind while working on ongoing activities, one has to monitor the environment to initiate the action at the appropriate time, and one has to perform the intended action according to the previously planned intention (Ellis, 1996). …