Proactive & Retroactive Interference

The most frequent reason for forgetting information is difficulty in transferring it from working memory to long-term memory. In addition, we can forget because of an inability to recall information that is in long-term memory. This section will discuss specific explanation for forgetting.
Fading occurs when we can no longer recall information from our memory because of disuse. In short-term memory, fading can occur very rapidly - in some cases after just a few seconds. When information fades from working memory, it disappears because the short-term space was needed for other incoming information. We can prevent this type of fading by continuing to focus attention on the information, by constantly rehearsing it, or by transferring it to long-term memory.
Once information has been transferred to long-term memory, most theorists believe that it is stored there permanently. When information fades from long-term memory, what really fades is the link; that is, we cannot find a way to retrieve it - it's there, but we just can't find it. We can prevent this kind of fading by encoding the information as meaningfully as possible, by frequently retrieving it, by actively restoring it whenever we do retrieve it, and by using effective memory search strategies.


Interference occurs when information gets confused with other information in our long-term memory. Interference can occur either retroactively or proactively. Retroactive interference occurs when previously learned information is lost because it is mixed up with new and somewhat similar information. For example, if you learn the contents of this chapter today, new information presented to you tomorrow could cause you to become confused about the contents of this chapter. A history student could study the causes and events of the American Revolutionary War and understand these thoroughly. Several weeks later the student could study the causes and events of the American Civil War. If the student thereafter had trouble remembering the causes and events of the Revolutionary War, this would be an example of retroactive interference.


Retroactive interference occurs when information works backwards to interfere with earlier information - just as a retroactive pay raise given in July might work backwards to influence pay days from January to June.


Figure 6.2. Proactive Interference (top) and Retroactive Interference (bottom). Proactive interference occurs when current information is lost because it is mixed up with previously learned, similar information. For example, you could have trouble learning the contents of this chapter because it conflicts with preconceived notions in your mind regarding the same topic. Returning to the history example described earlier, if the student who had learned about the Revolutionary War thereafter studied the Civil War and had trouble remembering the events of the Civil War, this would be an example of proactive interference.


Distortion refers to the misrepresentation of information that occurs when an imperfect image is recalled from long-term memory. It is not really a separate type of forgetting, but rather a combination of the previous three types. For example, when I returned to a high school reunion, I once discovered that many of my vivid recollections of my baseball career were distorted. I had clear memories of various heroic achievements, which I had dutifully narrated to my wife and children, and I firmly believed these to be true. Written and verbal evidence at the reunion repudiated my testimony. What seems to have happened is that some of the less pleasant aspects had faded from my memory. In addition, I apparently reconstructed a few situations in my post-game mental analyses, and when I tried to recall the incidents after several intervening years I tended to remember these more pleasant fantasies in place of the true accounts of the games. Likewise, although I passed a test on atomic fusion and fission a long time ago, when one of my children recently asked me a question about fusion, I gave an answer that blended the two concepts.
A final term related to forgetting is suppression. This is a term derived from Freudian psychotherapy that refers to the subconscious urge from within our personalities to obliterate unpleasant or threatening information from our memories. For example, an adolescent who had been abused as a child may be unable to recall specific instances of abuse, even though these were numerous, because he had suppressed them. Suppression is not an important cause of forgetting in most classroom settings. If a student says she forgot her Spanish "because she hated the teacher," her forgetting is probably because she has avoided contact with the subject matter rather than because of an emotional trauma.