Intuitively, this suggests—and major theoretical models argue—that recording overlapping memories as though they were unrelated is the best way to minimize memory interference. It's hardly surprising, therefore, that reactivating older memories during fresh encoding has been linked to less memory interference. Indeed, this is what happens when we try to memorize a list of items while responding to questions about other memories: The answers to the secondary questions affect how well we remember the first set of words or pictures.
However, this effect has only been demonstrated in laboratory settings where there are no distractions from anything else going on in the participant's life. When people try to encode multiple memories simultaneously in the real world, it can lead to the formation of related memories, which might not be desirable.
For example, if you're trying to remember something that happened last week but at the same time remember something that happened last year when you went on holiday to Spain, these will likely be encoded as two separate memories rather than one memory with a special section for "last year's holiday in Spain". This is because there was so much else happening last week (like meeting with friends, studying for exams) and so much else last year (like going to Egypt for Christmas), that it's unlikely that these events will be remembered together.
The lesson here is that if you want to remember something, focus on it exclusively for as long as possible without any distractions.
Interference from overlapping memories is a major component to forgetting. For example, if you were to try to remember both that you had lunch with your friend on Tuesday and that you saw your neighbor on Thursday, then there would be significant interference due to the overlap between the two events. Thus, it might help to record each one separately by describing what happened on each day instead of trying to remember both occasions.
There are several different methods used to reduce memory interference, including testing, blocking, and segregation. These techniques can all be used together or alone to good effect. For example, you could test yourself after writing down each event to see whether they come back to mind. If so, there is likely to be interference between them and you should write them down again in a different place or time. Blocking events that follow each other too closely in time allows you to forget the first event while still preserving information about the second.
Finally, segregation involves dividing up your environment into separate zones where you avoid placing items that could overlap in memory.
According to interference theory, forgetting happens when memories interact with and disturb one another; in other words, forgetting occurs as a result of interference from other memories (Baddeley, 1999). In other words, later learning interferes with previous learning by disrupting old memories. Memories that are close together in time will tend to interfere with each other because they're stored in similar parts of the brain. Memories that are more distant in time will not usually interfere with each other because they have had enough time to separate from each other's storage locations.
Interference can be divided up into two main types: proactive and reactive. Proactive interference occurs when learning new information activates existing memories which then becomes masked out by its counterpart memory. This means that any new information we learn will be obscured by our previous knowledge. An example of this would be if you were asked questions about France before taking an exam on that country. When answering survey questions, you would likely give an incorrect answer because you forgot what you learned about it earlier. Your current knowledge is interfering with your ability to remember what you've already learned! Reactive interference occurs when learning new information triggers thoughts or feelings associated with an old memory, causing that old memory to become masked out by its counterpart. For example, if you were asked questions about France during the exam but got nervous thinking about the country, this would cause you to forget how to answer the survey questions.