Interference theory is a scientific concept dealing with the way memories are stored in a person’s brain. According to interference theory, older and newer memories can interfere with each other. New memories can make older memories harder to recall, and old memories can make new memories somewhat hard to retain. There is a fair amount of scientific evidence supporting interference theory, but the exact mechanism behind it isn’t fully understood.
Generally speaking, memories only interfere with each other when they are focused in similar thinking areas. For example, if an individual where to spend many years learning a martial art, mastering a very specific pattern of movements and reactions, those may become very deeply set in his mind. Once those memories are in place, it can make training in a new set of similar skills more difficult. The individual’s ability to retain new information might be overwhelmed by the deeply-ingrained training he received previously. If the person keeps working at it, the interference effect can potentially be overcome, but it is not always easy to do.
Interference theory can also work in the opposite way. A new memory could potentially interfere with an attempt to remember something old. Sometimes it takes a little while for a new memory to supersede the old one, but once it happens, it can potentially make recall fairly difficult. Most experts generally agree that the old memories aren’t actually lost when they get replaced. Instead, they are thought to simply be somewhat inaccessible. An example of an old memory being replaced would be learning a new email address or password and then not being able to recall an older one.
One way scientists have studied interference theory is through experiments with memorization. Subjects in these studies are generally asked to memorize something, like a list or names of people in pictures, and once the information is fully learned, they are asked to learn even more similar information. Generally speaking, the results of these tests have conclusively shown that the person’s memory performance continually decreased with each additional bout of memorization.
There are many ways in which interference theory could potentially affect someone’s day-to-day life experience. For example, if people are ever asked to adapt to a new way of doing things in their jobs, they might find that memory interference greatly hampers their progress. Sometimes people have a great deal of difficulty unlearning old patterns of behavior.