Interference: Does learning new things block your old memories?
We all know that learning a new language is good for your brain, but is it true that when you learn a new language you will forget the old language you have learned before?
Do you remember what you had for dinner two weeks ago? Now choose your favorite trip from a couple of years ago. How much do you remember from that trip? The chances are that you do not remember what you had for dinner but you do remember something about your trip, although it took place much earlier than the meal.
This example shows that forgetting is not simply memories decaying with time. Our memories crucially depend on cues. A cue is essentially anything (such as a physical object, situation, time period, word, question, concept, etc.) which is paired with a memory trace and which must be activated for the memory trace to be retrieved.
If we pair the same cues with multiple memory traces then it will be difficult to retrieve one particular trace because once the cue is activated, the activation will spread to all paired memory traces at once and these will compete for entry to consciousness.
Coming back to the example above, if you usually dine in the same place, many different meals will become associated with the same cues (the dining environment). Therefore, it will be hard to retrieve the specific meal that you enjoyed a week ago. In contrast, you probably have not been on the same trip many times before, therefore it is easier to remember its details because they context of the trip is not paired with any other memories.
The disruption of memories by other memories which are paired to the same cues is called “interference”. You may have experienced interference yourself if you ever studied a second language. Interference may have caused you to be unable to retrieve vocabulary from one language. Instead, vocabulary from the other language popped to your mind. In this case, interference did not necessarily cause a loss of memory, but the memory trace became blocked thus temporarily inaccessible.
How to make children love learning and focus on learning is a interesting topic to be known. Research has found that the only way to overcome blocking interference is by making conscious effort to recover the correct memory trace (and have patience as this may take some time). Interference may, however, also cause a permanent loss of memory. Scientists who study memory call this the retrieval-induced forgetting effect (RIF).
As a demonstration, consider the following experiment: Students studied 10 geographical facts about each of 2 islands (A and B). They subsequently practiced retrieving 5 out of 10 facts for island A. Afterwards, their knowledge of these facts was tested.
What do you think happened to students’ memory about island A?
Unsurprisingly, retrieval practice boosted retention for the 5 facts that were practiced (the percentage of correct answers was greater than for island B). However, it also worsened the memory for the 5 facts about island A that were not practiced (again compared to island B). What caused this effect?
The island A serves as the context cue for information about island A, whereas island B serves as the context cue for information about island B. When the 5 facts about island A were retrieved from memory, their connection with the context cue was strengthened and the connection of the remaining 5 facts with the context cue was weakened (see “Testing effect”).
The main implication of this study for learning is that selective practice testing substantially boosts performance for the practiced items but can also worsen the performance for the unpracticed items. How can we combat forgetting caused by interference?
One way we can overcome interference is by making it explicit. If there are concepts that you get mixed up frequently then put them side by side and re-study them at the same time.
The general idea is that whatever you are studying, it is good practice to make different concepts as distinctive as possible. This forces your brain to encode them as dissimilar memory traces. You can achieve this by stressing the differences between different concepts from your study material (by comparing and contrasting, for instance).
Another effective strategy is to integrate the concepts. For instance, if you are memorizing the members of a particular animal/plant family, then try to find all possible relations between the members. When you’re later retrieving these members, they will no longer compete for access to consciousness as they will be encoded closely together in an integrative manner. Instead of one concept blocking the other, they will be retrieved simultaneously.
Scientists have found that our study goals also impact on how well we overcome interference. Students who focus on comparative performance (how well they do compared to other students) tend to use superficial processing (do not look for relations among concepts), whereas students who aim for mastery tend to use more deeper processing, such as establishing connections between different concepts.
In summary, we recommend the following:
·Re-study concepts that you confuse
–Use comparing and contrasting to find differences between the concepts
–Integrate the concepts (find the relations between them)
·Aim for mastery in a subject, do not pay attention to other people’s performance