Another of my long-term interests is human memory and my personal library has always had lots of memory books, starting with The Memory Book on up to Moonwalking with Einstein, with a diversion through Francis Yates' magisterial The Art of Memory.
My last literature review project as a PhD student combined these two interests. It was on the topic of prospective memory, a charmingly oxymoronic term that has been described as "remembering to remember." Herewith, a post that compresses some of that research because I thought it was too interesting not to share.
Prospective vs. Retrospective
Its opposite, retrospective memory, is what most of us are familiar with: a memory of an event that occurred in the past. This type of memory has been thoroughly researched for decades and has spawned a bewildering number of models: visual memory, semantic memory, autobiographical memory, sense memory, location memory, working memory, etc. We use retrospective memory to remember a small detail from a single day in our childhood or information we crammed the night before the test or hours of Monty Python sketches. (I am surprised that there are so many different conceptual models attempting to describe only certain aspects of memory and that there is still no one model that encompasses all of them.)
By contrast, prospective memory (PM) research has only been actively studied over the last 20 years and the research protocols are still being worked out. Also, prospective memory is about remembering a specific piece of information that must be recalled at a specific time in the near future. Prospective memory’s two key components are 1) remembering to do a task and 2) executing the task at the opportune moment. If I forget to do the task at the time it should be done, the task is said to have failed. If I remember to do the task, but after the opportune moment has passed, then the task is considered failed.
For example, I need to buy pasta for dinner. The prospective component of that task is remembering that I need to buy the pasta on the way home from work. If I remember to do so as I drive past the grocery store, then I have a chance of successfully completing the task. I may not have thought of the task all day, yet I may spontaneously recall it when I see the Harris Teeter sign from the road. This means I have to interrupt my foreground task (driving home) to execute the PM task and then resume the foreground task. However, if I remember to buy the pasta only after I pull into my driveway at home, then I have failed the prospective memory task because the optimal time for its completion has passed. Prospective memory includes not just remembering the task to be completed, but also successfully carrying out the intended action. And after I've completed the task, I can safely forget all about it.
(Retrospective memory plays a role in any PM task. After all, I have to remember how to drive a car, the directions to the store, the brand of pasta to buy, and so on.)
An interesting note that is struck by some of the literature is the social/moral aspect of prospective memory failure. If one forgets an address or a phone number, it is simply chalked up to a failure in retrospective memory (“I’ve always had a bad memory for names”); it is seen as a property dissociated from the person. Yet, a failure of prospective memory may call my reliability into question; my wife may label me as “careless” or “complacent” (among other things) (Winograd, 1988; McDaniel and Einstein, 2007). I can handle breaking a promise to myself, but if you were depending on me to execute the task, then social pressure may affect how I choose to remember the intention (Meacham, 1988).
PM is also critical in medication adherence, which is a tremendously active and rich research domain in its own right. I could forget to take my medicine at the right time(s) or take it too often. Also, most memory errors made by airline pilots tend to be prospective in nature.
A PM task can fail for multiple reasons: I didn't encode the task properly, I was distracted when I attempted to encode the task or missed the retrieval cue, or I was doing some habitual action -- like commuting or getting dressed -- that interfered with the cue, etc. If I am on auto-pilot when driving home from work, then I may not remember to turn right instead of left and so we have no pasta for supper.
McDaniel and Einstein (2007) recount a heartbreaking anecdote of a new father whose failures of prospective memory—which included not ensuring a potent enough reminder cue and performing actions outside of his daily routine—led to the suffocation of his infant son in the back of his locked car. In this case, the father put his infant son's car seat in the back and the child fell asleep. As the man drove to work he fell into the daily rhythm of his commuting habit, thought about his workday, turned to go to work instead of turning the other way to go to the daycare center, parked, and exited the car having totally forgotten about his son. The authors emphasize that failures of prospective memory are not moral failings, but instances where the human cognitive processes are under such stress—interruptions, lack of sleep, too much sensory input—that the task cannot be recalled.
There are PM skeptics to be sure, and they make damnably good points.
For one thing, you can almost effortlessly recall lots of details about what you did and where you went today, even though you may not have paid much attention to events at the time. Retrospective memory happens without our even trying.
Prospective memory, on the other hand, requires that you be mindful, pay attention, and burn some cognitive energy considering where and what you'll be doing so you can encode a persistent cue in your environment to trigger the PM task. That could mean setting an alarm on your cell phone (time-based cue) or knowing that you'll see the Harris Teeter sign on the way home (event-based cue). But is the PM task really a memory task in this case or just good planning? PM may only be a convenient -- and confusingly named -- blanket term encompassing diverse processes: behavior, attention, awareness, planning, monitoring, and so on.
Crowder (1996) employed a devastatingly simple rejoinder to the use of the term “prospective memory,” a term that he believed distracted researchers from the real problem under study. If one took the phrase “I must remember to do that task” and removed the words “remember to,” then the problem simplified from one of memory to one of planning and intention -- "I must do that task." Revising “forget to perform” to “fail to perform” yields the same result (Crowder, 1996).
There is also the suspicion that, because prospective memory is explicitly defined as “successfully carrying out the intention,” what should really be studied are how people set intentions, what are the cognitive processes backing them, and so on. Memory is about forgetting or remembering; successfully carrying out a remembered promise is about something other than memory (social rewards or self-image, for example) (Crowder, 1996). Intention as a concept could be subdivided into the memory for the intention, remembering the intention, and then executing the intention (Smith, 2008).
If you want more (more! MORE!) then hie thee to the Wikipedia entries linked above. Suffice to say, it's a fascinating topic.
The next post will be about strategies to increase the chances of successfully completing a PM task. My references and other articles of interest follow below.
Bower, G. H. (2000). A brief history of memory research. In E. Tulving & F. I. Craik (Eds.), The Oxford Handbook of Memory (pp. 3-32). Oxford: Oxford University Press.
Craik, F. I. M., & Kerr, S. A. (1996). Prospective Memory, Aging, and Lapses of Intention. In M. Brandimonte, G. O. Einstein, & M. A. McDaniel (Eds.), Prospective Memory: Theory and Applications (pp. 227-237). Mahwah, New Jersey: Lawrence Erlbaum Associates, Publishers.
Crowder, R. G. (1996). Commentary: The Trouble with Prospective Memory: A Provocation. In M. Brandimonte, G. O. Einstein, & M. A. McDaniel (Eds.), Prospective Memory: Theory and Applications (pp. 143-147). Mahwah, New Jersey: Lawrence Erlbaum Associates, Publishers.
Dobbs, A. R., & Reeves, M. B. (1996). Prospective Memory: More Than memory. In M. Brandimonte, G. O. Einstein, & M. A. McDaniel (Eds.), Prospective Memory: Theory and Applications (pp. 199-225). Mahwah, New Jersey: Lawrence Erlbaum Associates, Publishers.
Dodhia, R. M., & Dismukes, R. K. (2009). Interruptions create prospective memory tasks. Applied Cognitive Psychology, 23(1), 73-89.
Einstein, G. O., McDaniel, M. A., Marsh, R. L., & West, R. (2008). Prospective memory: Processes, Lifespan Changes, and Neuroscience. In H. L. Rodiger III & J. H. Byrne (Eds.), Cognitive Psychology of Memory (Vol. 2, pp. 867-892). Oxford: Elsevier.
Ellis, J. A. (1988). Memory for Future Intentions: Investigating Pulses and Steps. In M. M. Gruneberg, P. E. Morris, & R. N. Sykes (Eds.), Interpersonal Relations and Prospective Remembering (Vol. Some Observations on Prospective Remembering, pp. 371-376). Chichester: John Wiley & Sons.
Ellis, J. A. (1996). Prospective Memory of the Realization of Delayed Intentions: A Conceptual Framework for Research. In M. Brandimonte, G. O. Einstein, & M. A. McDaniel (Eds.), Prospective Memory: Theory and Applications (pp. 1-22). Mahwah, New Jersey: Lawrence Erlbaum Associates, Publishers.
Ellis, J. A., & Cohen, G. (2008). Memory for intentions, actions, and plans. In G. Cohen & M. A. Conway (Eds.), Memory in the Real World (pp. 141-172). New York: Psychology Press.
Elsweiler, D., Ruthven, I., & Jones, C. (2007). Towards memory supporting personal information management tools. Journal of the American Society for Information Science and Technology, 58(7), 924-946.
Elsweiler, D., Baillie, M., & Ruthven, I. (2008). Exploring memory in email refinding. ACM Trans. Inf. Syst, 26(4), 1–36.
Gollwitzer, P. M. (1999). Implementation intentions. Strong effects of simple plans. American Psychologist, 54, 493-503.
Graf, P., & Uttl, B. (2001). Prospective memory: a new focus for research. Conscious Cogn, 10(4), 437-450.
Guimond, A., Braun, C. M. J., Rouleau, I., & Godbout, L. (2008). The relative importance of suboperations of prospective memory. Applied Neuropsychology, 15(3), 184 - 193.
Harris, J. E. (1984). Remembering to do things: A forgotten topic. In J. E. Harris & P. E. Morris (Eds.), Everyday Memory, Actions, and Absent-Mindedness (pp. 71-92). London: Academic Press.
Hicks, J. L., Marsh, R. L., & Russell, E. J. (2000). The properties of retention intervals and their affect on retaining prospective memories. Journal of Experimental Psychology: Learning, Memory, and Cognition, 26(5), 1160 - 1169.
Kliegel, M., McDaniel, M. A., & Einstein, G. O. (2008). Preface. In M. Kliegel, M. A. McDaniel, & G. O. Einstein (Eds.), Prospective Memory: Cognitive, Neuroscience, Developmental, and Applied Perspectives (p. xiii). New York: Lawrence Elbaum Associates.
Koriat, A., & Ben-Zur, H. (1988). Remembering That I Did It: Processes and Deficits in Output Monitoring. In M. M. Gruneberg, P. E. Morris, & R. N. Sykes (Eds.), Practical Aspects of Memory: Current Research and Issues (pp. 203-208). Chichester: John Wiley & Sons.
Kvavilashvili, L., & Ellis, J. A. (1996). Varieties of Intention: Some Distinctions and Classifications. In M. Brandimonte, G. O. Einstein, & M. A. McDaniel (Eds.), Prospective Memory: Theory and Applications (pp. 23-51). Mahwah, New Jersey: Lawrence Erlbaum Associates, Publishers.
Marsh, R. L., Hicks, J. L., & Landau, J. D. (1998). An investigation of everyday prospective memory. Memory and Cognition, 26, 633–643.
Marsh, R. L., Hicks, J. L., & Cook, G. I. (2005). On the Relationship Between Effort Toward an Ongoing Task and Cue Detection in Event-Based Prospective Memory. Journal of Experimental Psychology: Learning, Memory, and Cognition, 31(1), 68 - 75.
McDaniel, M. A., & Einstein, G. O. (2007). Prospective Memory: An Overview and Synthesis of an Emerging Field. Thousand Oaks, CA: Sage Publications, Inc.
Meacham, J. A. (1988). Interpersonal Relations and Prospective Remembering. In M. M. Gruneberg, P. E. Morris, & R. N. Sykes (Eds.), Some Observations on Prospective Remembering (Vol. Remembering That I Did It: Processes and Deficits in Output Monitoring, pp. 354-359). Chichester: John Wiley & Sons.
Park, D. C., & Kidder, D. P. (1996). Prospective Memory and Medication Adherence. In M. Brandimonte, G. O. Einstein, & M. A. McDaniel (Eds.), Prospective Memory: Theory and Applications (pp. 369-390). Mahwah, New Jersey: Lawrence Erlbaum Associates, Publishers.
Rabbitt, P. (1996). Why Are Studies of "Prospective Memory" Planless? In M. Brandimonte, G. O. Einstein, & M. A. McDaniel (Eds.), Prospective Memory: Theory and Applications (pp. 239-248). Mahwah, New Jersey: Lawrence Erlbaum Associates, Publishers.
Sellen, A. J., Louie, G., Harris, J. E., & Wilkins, A. J. (1997). What brings intentions to mind? An in situ study of prospective memory. Memory, 5(4), 483–507.
Smith, R. E. (2003). The cost of remembering to remember in event-based prospective memory: Investigating the capacity demands of delayed intention performance. Journal of Experimental Psychology-Learning Memory and Cognition, 29(3), 347–360.
Smith, R. E. (2008). Connecting the Past and the Future: Attention, Memory, and Delayed Intentions. In M. Kliegel, M. A. McDaniel, & G. O. Einstein (Eds.), Prospective Memory: Cognitive, Neuroscience, Developmental, and Applied Perspectives (pp. 29-52). New York: Lawrence Erlbaum Associates.
Thöne-Otto, A. I. T., & Walther, K. (2003). How to design an electronic memory aid for brain-injured patients: Considerations on the basis of a model of prospective memory. International Journal of Psychology, 38(4), 236–244.
Winograd, E. (1988). Some Observations on Prospective Remembering. In M. M. Gruneberg, P. E. Morris, & R. N. Sykes (Eds.), Remembering That I Did It: Processes and Deficits in Output Monitoring (Vol. Practical Aspects of Memory: Current Research and Issues, pp. 348-353). Chichester: John Wiley & Sons.