Why do we forget?
Rate of Forgetting
The first scientific study of forgetting was done in the 19th century by the German psychologist Hermann Ebbinghaus. Although his methods were crude by modern standards, he discovered one principle that has stood the test of time. Ebbinghaus found that after something is learned, the rate of forgetting is negatively accelerated; that is, the major proportion of forgetting occurs early in the period after learning takes place. His findings and subsequent research indicate that to reduce forgetting to a minimum, one should review material soon after learning it. The longer the wait, the less effective the review will be.
What is "forgetting"?
Forgetting is the inability to bring memories to consciousness. A traditional theory attributes forgetting to the decay of memory information with time, but modern psychology tends to regard interference from other memories as critical. Forgetting is viewed as an inability to retrieve stored information because other information "gets in the way".
Theories of Forgetting
After a person learns something, it is not forever available in his mind. Three main theories explaining why forgetting takes place have been put forward. The first theory, advanced mainly by psychoanalysts, states that forgetting is purposeful; that is, persons forget intentionally because they do not want to have the memory in their mind. As a result, unpleasant experiences tend to be less well remembered than pleasant experiences.
Most psychologists accept this theory only in part. For example, they say that a schoolchild is more likely to forget to do his homework than to forget to watch a favorite television program. It is also true that a person may be unable to recall highly unpleasant emotional experiences he has endured. However, the theory does not help explain a great deal of the ordinary forgetting that occurs in everyday life.
The second theory is sometimes called the theory of disuse. It states that forgetting occurs because the material is not used, just as muscles lose their effectiveness if they are not used. It is true that forgetting needs time to occur, so that the longer the material is not used, the greater the amount of forgetting.
However, research indicates that disuse of information over a period of time is not the only cause of forgetting. Other factors, such as what happens during the interim, are also . important. For example, two equal groups may learn the same chemical equations, after which the first group goes to sleep and the second group learns additional equations. If both groups are later tested on their memory of the original set of equations, it would be found that the first group's recall is better than that of the second group, which had to learn more material immediately after.
The third theory of forgetting, which is widely accepted by psychologists, holds that forgetting is the result of interference. In some cases the interference may come from experiences that occurred before the learning took place. This type of interference is known as proactive inhibition. For example, if a child has previously learned to spell the words "lean", "clean", "really", and "read", he may forget that "sheet", which has the same vowel sound, is not spelled "sheat." Perhaps slightly less important is retroactive inhibition, an interference that comes from subsequent experiences. An example of retroactive inhibition is that of the two groups learning the same chemical equations. The poorer performance of the second group is due to retroactive inhibition. Therefore one's experiences interact with both past and future experiences.