The calendar functions of devices such as personal digital assistants (PDAs) and smartphones have always been types of time-based prospective memory aids. An item to be remembered in the future (e.g., go to meeting at 4 pm) is entered into the calendar and when that time arrives we are reminded with a notification or alarm (hence the term time-based).
Prospective memory is remembering to perform an action in the future. Whereas retrospective memory is remembering something from the past. In many ways, prospective memory is much more important, from a human factors prospective, than retrospective memory. For absent-minded people like me, prospective memory failures (like missing a meeting) is of low consequence (depending on who I am unintentionally blowing off).
But imagine the situation where a nurse forgets to carry out a procedure, a doctor forgets to remove gauze in a patient, or when a patient forgets their medication instructions. The consequences for prospective memory failure are much greater (and potentially deadly).
Prospective memory events can be “fired” by two main types of cues or “reminders”:
- The first is time-based (like the example above): At 3 pm, call cable company, or in 30 minutes call Chris.
- The other way is event-based: When I see Anne, let her know that the paper is due, or drop deposit check when I pass the ATM.
Electronic calendars are great at aiding time-based prospective memory tasks but only recently do they now cue event-based tasks. For example, phones using the Android operating system can download a program that tracks your location (using the phone’s GPS unit) to fire off a reminder based on your current location. So if you are near the grocery store it can remind you to pick up bread (event-based cue).
I recently discovered a feature in Palm WebOS phones (like the new Palm Pre) that can fire off reminders based on who you are communicating with (via phone conversation, instant messaging, or I think email). When I contact Anne (or she contacts me), a notification will remind me of what I needed to tell her.
Say that I need to tell Anne of an upcoming deadline when I see or hear from her. I select her contact entry and type in a note to myself to remind her. Next time I call her or we instant message I will receive this reminder:
Again, this is an event-based cue (communicating with Anne is the event) and not a time-based cue (there is no specific time when it might happen). Cool! More information about prospective memory can be found in this book (Google Books link) and countless articles.