Another explanation for how and why we forget has been in terms of disuse or decay (2, 3). Sometimes we forget things simply because we haven’t remembered it in awhile. For example, you can probably remember what you had for lunch yesterday. How about last week? Last month? Unless there was a reason for you to recall the contents of your lunch, you likely forgot it over time. Assuming that you have not had any reason to recall your lunch, you are most likely forgetting past lunches due to decay and not interference.
So how can forgetting – whether it’s caused by interference or decay – help us remember? Let’s take the simple example of remembering where you parked your car. You go out to the parking lot or garage and instead of sifting through a few ideas from today or last week about where you parked your car, you suddenly remember where you parked last Wednesday and Tuesday from 3 weeks ago, and the hundreds of other times you have parked your car. Some of these locations and memories may be helpful to you at present, but many are not.
Forgetting helps us be selective, strategic, about remembering. We don’t get overwhelmed with ALL of the possible information when we try to remember something because our memory system uses certain tricks and hints to help us remember certain things and forget others. We remember certain bits and pieces of information over others based on context, frequency, and recency. Things that we have had to remember frequently and most often typically come to mind much more easily. This also means that things we haven’t needed to remember frequently or recently don’t come to mind as easily.
Forgetting can be frustrating. But it’s the flip side to remembering. Forgetting helps you remember by presenting you with fewer options. Most of the memory strategies that we talk about can also be framed in terms of forgetting strategies. Practicing retrieval of certain information helps you recall that information and forget other information (4). Spacing and interleaving take advantage of difficulty of retrieving information, or potential forgetting, to improve memory (5, 6).
All of this is to say – don’t be discouraged or hard on yourself when you forget something. Forgetting is actually a very useful part of your memory!
Underwood, B. J. (1957). Interference and forgetting. Psychological review, 64(1), 49.
McGeoch, J.A. (1932). Forgetting and the law of disuse. Psychological Review. 39 (4): 352–370.
Bjork, R. A., & Bjork, E. L. (1992). A new theory of disuse and an old theory of stimulus fluctuation. In A. Healy, S. Kosslyn, & R. Shiffrin (Eds.), From learning processes to cognitive processes: Essays in honor of William K. Estes (Vol. 2, pp. 35-67). Hillsdale, NJ: Erlbaum.
Anderson, M. C., Bjork, R. A., & Bjork, E. L. (1994). Remembering can cause forgetting: Retrieval dynamics in long-term memory. Journal of Experimental Psychology: Learning, Memory, and Cognition, 20, 1063-1087.
Bjork, R.A. (1994). Memory and metamemory considerations in the training of human beings. In J. Metcalfe & A. Shimamura (Eds.), Metacognition: Knowing about knowing (pp. 185-205). Cambridge, MA: MIT Press.
Mc Daniel, M. A., & Butler, A. C. (2011). A contextual framework for understanding when difficulties are desirable. In Successful Remembering and Successful Forgetting: A Festschrift in Honor of Robert A. Bjork (pp. 175-198). Taylor and Francis.